How do I remove a misbehaving package using either apt or apt-get?

I am trying to remove an apparently-corrupt package gammu-smsd.service.

When I run sudo apt remove gammu-smsd.service, I get the following result:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package gammu-smsd.service

I got to the point of wanting to remove this package because, while I was doing some cleanup, I was confronted with issues while attempting to install and delete packages that I had selected. Here’s the result of upgrading (updating is flawless).

Here’s the the result of running sudo apt upgrade.

Reading package lists...
Building dependency tree...
Reading state information...
Calculating upgrade...
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] Abort.

I was alerted by the 6th line (in above output) that there was a problem.
Once I learned that the culprit was gammu-smsd.service, I ran systemctl status gammu-smsd.service obtaining this result:

● gammu-smsd.service - SMS daemon for Gammu
     Loaded: bad-setting (Reason: Unit gammu-smsd.service has a bad unit file setting.)
     Active: inactive (dead)
       Docs: man:gammu-smsd(1)

Jul 18 20:15:18 LolouilaLawelima systemd[1]: /lib/systemd/system/gammu-smsd.service:9: Neither a valid executable name nor an absolute path: ${CMAKE_INSTALL_FULL_BINDIR}/gammu-smsd

Jul 18 20:15:18 LolouilaLawelima systemd[1]: gammu-smsd.service: Unit configuration has fatal error, unit will not be started.

Jul 18 20:56:24 LolouilaLawelima systemd[1]: /lib/systemd/system/gammu-smsd.service:9: Neither a valid executable name nor an absolute path: ${CMAKE_INSTALL_FULL_BINDIR}/gammu-smsd

Jul 18 20:56:24 LolouilaLawelima systemd[1]: gammu-smsd.service: Unit configuration has fatal error, unit will not be started.

Jul 18 20:56:25 LolouilaLawelima systemd[1]: /lib/systemd/system/gammu-smsd.service:9: Neither a valid executable name nor an absolute path: ${CMAKE_INSTALL_FULL_BINDIR}/gammu-smsd

Jul 18 20:56:25 LolouilaLawelima systemd[1]: gammu-smsd.service: Unit configuration has fatal error, unit will not be started.

Jul 18 21:18:31 LolouilaLawelima systemd[1]: /lib/systemd/system/gammu-smsd.service:9: Neither a valid executable name nor an absolute path: ${CMAKE_INSTALL_FULL_BINDIR}/gammu-smsd

Jul 18 21:18:31 LolouilaLawelima systemd[1]: gammu-smsd.service: Unit configuration has fatal error, unit will not be started.

Jul 18 21:18:33 LolouilaLawelima systemd[1]: /lib/systemd/system/gammu-smsd.service:9: Neither a valid executable name nor an absolute path: ${CMAKE_INSTALL_FULL_BINDIR}/gammu-smsd

Jul 18 21:18:33 LolouilaLawelima systemd[1]: gammu-smsd.service: Unit configuration has fatal error, unit will not be started.

How can I remove and/or purge a package that apt cannot find?

Following the suggestion from comments and running sudo apt remove gammu-smsd, I got:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  libgammu-i18n libgammu8 libgsmsd8
Use 'sudo apt autoremove' to remove them.
The following packages will be REMOVED:
  gammu-smsd
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
1 not fully installed or removed.
After this operation, 179 kB disk space will be freed.
Do you want to continue? [Y/n] 
(Reading database ... 737130 files and directories currently installed.)
Removing gammu-smsd (1.41.0-1) ...
Failed to stop gammu-smsd.service: Unit gammu-smsd.service not loaded.
invoke-rc.d: initscript gammu-smsd, action "stop" failed.
dpkg: error processing package gammu-smsd (--remove):
 installed gammu-smsd package pre-removal script subprocess returned error exit status 1
dpkg: too many errors, stopping
Failed to start gammu-smsd.service: Unit gammu-smsd.service has a bad unit file setting.
See system logs and 'systemctl status gammu-smsd.service' fo
r details.
invoke-rc.d: initscript gammu-smsd, action "start" failed.
● gammu-smsd.service - SMS daemon for Gammu
     Loaded: bad-setting (Reason: Unit gammu-smsd.service ha
s a bad unit file setting.)
     Active: inactive (dead)
       Docs: man:gammu-smsd(1)

Jul 18 23:16:57 LolouilaLawelima systemd[1]: /lib/systemd/sy
stem/gammu-smsd.service:9: Neither a valid executable name n
or an absolute path: ${CMAKE_INSTALL_FULL_BINDIR}/gammu-smsd
Jul 18 23:16:57 LolouilaLawelima systemd[1]: gammu-smsd.serv
ice: Unit configuration has fatal error, unit will not be st
arted.
Jul 18 23:16:59 LolouilaLawelima systemd[1]: /lib/systemd/sy
stem/gammu-smsd.service:9: Neither a valid executable name n
or an absolute path: ${CMAKE_INSTALL_FULL_BINDIR}/gammu-smsd
Jul 18 23:16:59 LolouilaLawelima systemd[1]: gammu-smsd.serv
ice: Unit configuration has fatal error, unit will not be st
arted.
Jul 18 23:22:08 LolouilaLawelima systemd[1]: /lib/systemd/sy
stem/gammu-smsd.service:9: Neither a valid executable name n
or an absolute path: ${CMAKE_INSTALL_FULL_BINDIR}/gammu-smsd
Jul 18 23:22:08 LolouilaLawelima systemd[1]: gammu-smsd.serv
ice: Unit configuration has fatal error, unit will not be st
arted.
Jul 18 23:22:11 LolouilaLawelima systemd[1]: /lib/systemd/sy
stem/gammu-smsd.service:9: Neither a valid executable name n
or an absolute path: ${CMAKE_INSTALL_FULL_BINDIR}/gammu-smsd
Jul 18 23:22:11 LolouilaLawelima systemd[1]: gammu-smsd.serv
ice: Unit configuration has fatal error, unit will not be st
arted.
Jul 18 23:22:12 LolouilaLawelima systemd[1]: /lib/systemd/sy
stem/gammu-smsd.service:9: Neither a valid executable name n
or an absolute path: ${CMAKE_INSTALL_FULL_BINDIR}/gammu-smsd
Jul 18 23:22:12 LolouilaLawelima systemd[1]: gammu-smsd.serv
ice: Unit configuration has fatal error, unit will not be st
arted.
dpkg: error while cleaning up:
 installed gammu-smsd package post-installation script subpr
ocess returned error exit status 1
Errors were encountered while processing:
 gammu-smsd
Processing was halted because there were too many errors.
E: Sub-process /usr/bin/dpkg returned an error code (1)

sudo sed -i 's|${CMAKE_INSTALL_FULL_BINDIR}|/usr/bin|g' /lib/systemd/system/gammu-smsd.service

sudo systemctl daemon-reload
sudo systemctl restart gammu-smsd