Can a low energetic photon be reflected?

Ionization is not the only process by which light can interact with matter. For example if you consider a crystalline solid, a photon can excite a collective vibrational mode (this is called a phonon and has the same energy levels of the quantum harmonic oscillator), thus a low energetic photon can excite a low frequency vibrational mode. Note that not all frequencies are allowed (in particular there is an upper limit to it), but low frequencies are always allowed.

Some other processes, instead do not occur at low energy. You mentioned ionization, but diffraction is another example. Diffraction in crystalline solids follow Bragg's law:

$nlambda =2d cdot sintheta quad$ where $ninmathbb N$ is the order of diffraction

You can see immediately that if $lambda > 2d$ you do not get diffraction (of any order).

When a photon hits a solid the photon gets absorbed only by valence electrons if there are available energy-momentum states available(not occupied)which have the same momentum and energy with the electron and the photon seperately.

A solid material may have nearly-free electrons which will respond to the electric field of any photon. Mirrors reflect because of an aluminum or silver layer. Window glass is transparent because it lacks conduction electrons like a metal, but there is still somewhat of a reflection possible, because every atom has the potential to respond to an electric field (Stark effect and/or the magnetic field (Zeeman effect) which comprise a photon.

It's a little more complicated for a crystal with spacing comparable to the photon wavelength, or an oilslick, or a semiconductor, but... well, all the complicated photon interactions is what makes our visual experience so rich; when you see a rainbow, enjoy it!