Unless they already have your phone number, I would never call the collections company with my own phones. They automatically update and call you while you’re already talking to them, and then lie that the phone number you gave them was always on file and they’ve contacted you hundreds of times. I tried to settle a small bill once that was some oversight from my wifes family, and was fully ready and willing to pay. The collections people gave me all sorts of run-arounds and couldn’t even stop lying in such a case. If they can’t function within the confines of the law and business in a simple non-contested thing, I wouldn’t bother in another time by myself.
There are consumer lawyers, in theory, who are supposed to handle this. (I say in theory, because I never found one interested in the federal fair debt law that they advertise on tv).
Sounds like a Breach of Contract or Breach of warranty, and tons of other claims.
I second the idea of disputing it with the bank. However, that won’t fix the “diversified” nonsense automatically.