Product: Debt collection

My name is XXXX XXXX and I previously had an account with XXXX XXXX XXXX, however, I continuously paid my account in a timely manner by way of XXXX XXXX pay. When I received my XXXX 2012 - XXXX 2012 ( service period ) bill ( approximately XXXX XXXX 2012 ) it stated I had an unpaid balance of {$160.00}, so I paid {$160.00} in cash at the XXXX XXXX XXXX on XXXX. located less than XXXX minutes from my residence. I checked my bill pay first and saw that the payment was sent but the check never cashed ( nearly one month after it was sent ). At that time I was most certain the check was lost and would not be cashed. So I called my bank and cancelled the check ( {$29.00} ), meaning I could make the payment and hopefully avoid a XXXX payment that would lead to extended wait time getting my money back and/or " having a bad mark on my credit report. I also talked to XXXX XXXX prior to stopping payment on this check and let the agent know so my account could be annotated. I wanted to ensure everything was done well, so again after I made the payment through the service center I called back XXXX XXXX customer service and I was assured by the agent that everything was documented within the system. During that conversation I also learned that the reason my account past due is because my account number was changed from XXXX XXXX XXXX XXXX to XXXX XXXX XXXX XXXX with a system update. I then updated my bill pay with the new account number ( XXXX etc ... ) and made the remaining balance payment of {$170.00} through my bank account ( totaling {$340.00} on my XXXX statement ). 
Then came time for me to move ( XXXX ) to XXXX XXXX WA. resulting in closing my account XXXX 2012 ( six months later ). I made my last payment before I left XXXX XXXX confident that all was well and good with my account. I even received check dated XXXX XXXX 2012 XXXX {$7.00} XXXX further ensuring that my account was well and good. However, long after I cashed the refund check from XXXX XXXX on my account I received a disturbing collection 's agency letter stating that I had an outstanding balance on my XXXX XXXX account in the amount of {$190.00}. This amount included a {$30.00} return check fee and {$160.00} unpaid balance. I asked the customer service rep, on-line technician how I can get my log-in and password from the internet and was told ( impossible ) because the account is closed. I also have asked the agents to simply review the system notes on my account to clear this matter up but apparently all the posting that the agent promised she added to my account had been purged from the system. I do n't know why a company would attempt to collect a payment for several months after an account is closed in good standing. Especially, when the system history notes ca n't go back that far and fully see the picture of those time periods. 
Note : My suggestion for their office is to leave notes from six months past on accounts or do n't attempt to collect from old customers that have closed their accounts in good standing. After 6 months has past that should be more than enough time for a company to clarify an account especially when it come to a returned check ( I paid my account and cancelled the check because of an account number change in which I had no knowledge of ). When the bill pay check initially came in it had the old account number on it and must have sat in someone 's inbox until after I had already closed my account and the technician notes were purged from my account.