I've had to deal with them multiple times.

They weren't angry with me. They were, however, obstinate. They disputed an education related credit. Each time I called them, they told me what documents they would need. I'd send it, and they'd continue the dispute. The cycle would repeat.

Here's what happened:

University sends me tax form. I file with my taxes.

"Just because they sent you the form doesn't mean you actually attended the school and paid your fees. Send us proof you paid them."

Sent proof of payments to the university.

"Just because you gave them money doesn't mean it was for tuition. For all we know they could be parking tickets. Send us the billing statement"

Called the university[1] to get a copy of the billing statement. Sent to the IRS to show the payments matched the tuition billed.

"Sorry, that's not enough. Send us a statement from the university with a line item showing the tuition was paid."

Sent it. They finally accepted it.

The university told me they'd never heard from any student that the IRS didn't simply accept the original tax form they send out.

[1] Keep in mind that this conversation happened 2-3 years after graduating.