Thank you for the reply. I've asked the HR team at CA why it was sent to collections but haven't heard back yet. Going through their ex-employee portal, there are notes that emails were sent to my old email address at CA, which - surprise! - no longer existed since I was no longer an employee at that point. They still know my home address and phone number, so there is zero reason why a postal letter from collections should have been the first knowledge of the debt on my end.

Should I contact the collections agency at all? Or, if they call, should I even answer? Not sure what precedents or expectations are set if I talk to them.

Also, I've read that if I negotiate a lower payment with collections, it would be reported as "paid as agreed" instead of "paid in full". Would this affect my credit at all? Would this even being sent to collections in the first place do anything to my credit?

And, oh yes, I'm going to waste as much of their time as possible!