file a complaint

Supposed to have a $297.56 credit on bill but Xfinity won't apply it.  I have had two video conferences with them recently and they say they will take care of it but nothing happens.    I have been to the Xfinity store numerous times.   I was supposed to have a $66.00 credit because we cancelled that subscription in January, and went to my name.   Then I got charged for February and  we weren't even subscribed but got billed anyway.