I have to pay an account with Universal Fidelity

Got a phone call on Friday the 25th of August from UF and they explained that they had taken over a retail store account that I had years ago with HSBC. They explained the balance of 3100.00 had to be paid in full or set up payment arrangements at 600.00 per month. I have not received a letter or any documentation from UF or HSBC regarding this. Anyways, I told them I would research it and for them to call me back on Monday. The issue was that I made all my payments online to HSBC and when I moved to another house, I didn't change my address on file and I never got any forwarding from them. Bottom line, I screwed up, but I didn't get any letters at all. To be honest, I forgot about the account. Well, here we are 10 months later and I now owe them 3100.00. I talked to a very nice woman on the phone Friday named Eiesha. Well, today, a man named DJ left a message on my phone stating that it was very important I call him back today to set something up with him. I explained that I have not received any documentation and cannot make a payment until I see something in writing. I agreed to make payment arrangements at 300.00 per month to get the account back to good status and clear this out. I told him I couldn't make a payment until the middle of September. That was unacceptable according to him. Keep in mind, it's August 29th, 3 days until the end of the month. Can we say quota? He explained that if I didn't make a payment that we will no longer be able to accept a payment arrangement and the balance would be do in full. I told him I would call him back and let him know. I received a call an hour later from Eiesha again, the same woman as Friday. She couldn't have been more helpful. She told me that they just received the account last Thursday and told me she would mail everything out to me and that I can setup payment arrangements whenever is financially good for me. I told her about my early conversation with DJ and she said that sometimes things are said that are not always 100% truthful. Bottom line, she is great and I have no problem paying my debt to people like her.