Product: Debt collection

XX/XX/XXXX ported my number to XXXX. By XX/XX/XXXX never received my bill so I called customer service and they said I had to wait until XX/XX/XXXX because the bill need to be generated. At that time I confirmed the amount owed of {$260.00} which was the remaining lease payments out of XXXX on my device. The amount they had in the system was an additional {$130.00} which would have been the next months service but I intentionally ported the number before the cycle as to avoid this. 
On XX/XX/XXXX I received a letter dated XX/XX/XXXX which stated I owed that {$130.00} -see attached. I responded with a hand written letter dated 1XXXXsee attached. 
Then on XX/XX/XXXX I received a bill dated XX/XX/XXXX stating I owed {$400.00}. -see attached. - I thought I had sorted this out ( see above ) so on XX/XX/XXXX I called again to confirm that IN FACT I owed {$260.00} which is due on XX/XX/XXXX. 
Thinking this was finally fixed XXXX  went about XXXX. On XX/XX/XXXX I paid {$60.00} leaving a balance of {$200.00} due on XX/XX/XXXX, as confirmed ( see above ). 
Then XX/XX/XXXX I received a letter stating I owed the balance of {$200.00} -see attached Then on XX/XX/XXXX I received a bill labeled YOUR LAST BILL that is dated XXXX-see attached. This bill shows a balance of {$200.00} due on XXXX {$7.00} late fee was attached??? 
Then on XX/XX/XXXX I received a phone call from customer service thanking me for my handwritten note from XX/XX/XXXX see attached and above and confirming my balance of {$200.00} would be paid by XX/XX/XXXX. I said but that I should not have a {$7.00} late fee-so they kindly removed it. I confirmed payment of {$200.00} would be received by the due date of XX/XX/XXXX. 
Then on XX/XX/XXXX I received a letter dated XX/XX/XXXX from a collection agency stating I owed {$200.00}. 
I called XXXX on XX/XX/XXXX and spoke with XXXX XXXX  whom did not understand why I received such conflicting bills etc, but that the policy was that 20 days it was automatically sent to collections. Well if I got my final bill as stated above on XX/XX/XXXX then why the collection on XX/XX/XXXX? 
I did in fact pay the balance of {$200.00} on XXXXsee the attached, this is well before the due date of XX/XX/XXXX or XX/XX/XXXX, XXXX still confused by the paper work to which due date is correct. Either way there is no reason for the collection and absolutely gross and blatant abuse of the fair credit reporting act- this should not be a negative or derogatory XXXX on my credit reports and should be deleted and restored as such! 
This is a classic case of the right hand not talking to the left hand. I called and they said there was nothing they could do. This is unfair and the balance has been paid! I owe nothing. This should not be reporting to the XXXX credit bureaus as a derogatory. I would like a courtesy deletion for their blatant mistake and at least a formal apology from the XXXX level. Furthermore, if XXXX would match the XXXX offer that I got ( saving {$40.00} a month on my bill ) I never would have left. Them. In fact this is one of the dumbest things Ive ever done -goin to XXXX XXXX 
XXXX should for my inconvenience of their mistake port my number back with matching unlimited service, buyout my XXXX contract and charging me {$100.00} a month like Im getting with XXXX now XXXX Doubt that will happen. Please this is wrong and erroneous on their part. Too bad I loved XXXX.