Send me my paid up letter

Last week I called in to your call center to find out how much my account is to my surprise I was told ny account is paid up I was shocked that the store just did let me keep paying and didn't even call me to day account is paid up so i asked the agent to send me a paid up letter she took my email and.did give me a ref 873774 but I nver got that paid up letter and also I think I might have overpaid and being credit since I was never notified that my account is up to date until I found in to call center the people who work at that store that purchase my item are extremely rude and have No Manners whatsoever if you miss a payment but can't tell you if you paid up I never want to do business with you guys again please send me my paid up letter and check my account because I'm sure I must have overpaid since I nver was notified I am paid up until I called the call center