Wrong Billed reported to all three Credit Bureau and No one knows how to generate Stipulation letter to customer.

I have requested for  multiple time for stipulation letter for more than 5 times  and no one is able provide a letter stating that " Comcast billed me wrong and reported Wrong to credit bureau which impacting my mortgage."   Comcast adjusted the entire bill and Comcast supposed to pay me back $1.52 after adjustment they have done. No one providing me Stipulation Letter from last 5 days and keep rotating me different departments and retail stores to get me a letter.