Yea definitely don't call, do everything in writing because the courts start with paper so paper trail is very important if you find Yourself in court.. If I were you Id read 15 usc 1692 (Fair Deb Collection Practices act) and look for the violations they are committing and use it against them to remove the account if its on your credit report. Ive helped my family with collections for a while now and ive been successful so give the FDCPA a read because it tells you exactly what they can't do such as threaten you like they did, well I woulda took it as a threat lol. They also can't tell you that you owe them money. You got this. If you see violations you should be compensated 1k for each violation under 15 usc 1692k. Also don't forget to use your friends The Consumer Financial Protection Bureau, Better Business Bureau, Your state Attorney General Good luck