What's a word to describe a person being deliberately unclear/obfuscatory

Disingenuous gets my vote:

1. lacking in frankness, candor, or sincerity; falsely or hypocritically

Although evasive or deceptive may fit, depending on specific usage.

I would say obtuse. The below is from OED.

Obtuse ADJECTIVE

1. Annoyingly insensitive or slow to understand: ‘he wondered if the doctor was being deliberately obtuse’

   1.1 Difficult to understand, especially deliberately so: ‘some of the lyrics are a bit obtuse’

From the ODO:

circumlocutory

ADJECTIVE

Using many words where fewer would do, especially in a deliberate attempt to be vague or evasive; long-winded. ‘he has a meandering, circumlocutory speaking style’

From Language Log:

... we find the expression in an episode of Yes Minister, in the mouth of a stunningly circumlocutory character:

Sir Humphrey: "Minister, I think there is something you perhaps ought to know."

Jim Hacker: "Yes Humphrey?"

Sir Humphrey: "The identity of the Official whose alleged responsibility for this hypothetical oversight has been the subject of recent discussion, is NOT shrouded in quite such impenetrable obscurity as certain previous disclosures may have led you to assume, but not to put too fine a point on it, the individual in question is, it may surprise you to learn, one whom your present interlocutor is in the habit of defining by means of the perpendicular pronoun."

Jim Hacker: "I beg your pardon?"

Sir Humphrey: "It was...I."

disobliging - to refuse or neglect to oblige; act contrary to the desire or convenience of; fail to accommodate.

perverse From the OED, perverse

Of a person, action, etc.: going or disposed to go against what is reasonable, logical, expected, or required; contrary, fickle, irrational.

My made-up example:

The agent gave me a lot of irrelevant information but perversely refused to answer my question, which I asked several times and in several ways.

perverse captures the sense that the OP had that "[they] seemed to have an agenda not to help me". Also the sense the OP had that they "deliberately" avoided answering. That is, they weren't stupid, they were perverse.

Example from the OED (same link as above):

1987 P. Farmer Away from Home (1988) 52 She just says, ‘So what?’ knowing she is being perverse, but not caring in the slightest.