Very unhappy customer - customer service is rediculous!

I called on May 5th to receive authorization to return 3 receivers to AT&T.  Authorization received and receivers taken to UPS on May 7th.  June billing still had the $30 dollar charge for the 3 returned receivers, I called and was told to be patient that once the boxes where checked into the warehouse - I would be credited back the money.  Same conversation for month of July - still not checked into warehouse.  Called again on September 19th and was told the representative that entered the return did not notate anything about giving credit back once equipment was received in the warehouse and that the issue would be turned over to resolution department and I should hear something back from them.  Never heard anything, call AGAIN on November 1st and talked with Mark and he understood my frustration and was not able to credit my account for the $30 a month charges  times 4 months but, he did see where I was credited a partial month from the date (Sep 19th - Oct 2) from the Sept 19th call and that was on the most recent bill.  Since Mark could not credit back to my account the $120 that I had paid - WHILE BEING PATIENT, he transferred me to Brianna in the compensation department.  After giving Brianna ALL of my information AGAIN .......... being put on hold several times AGAIN ........  her talking in circles and explaining back to me what is transpiring with my account (like I don't know) AGAIN ...........  I lost my cool and screamed at her that "if you can not credit back to my account the $120 then, I want to speak with your supervisor" - along with telling her that "I could not understand why a loyal 9 year customer had to go through all this bullcrap and to set up an appointment to come take it all out"  She asked me to hold AGAIN ..... while she tried to get her supervisor on the line.

At this point I put the call on speaker and started  listening to the AT&T recording - FOR THE NEXT HOUR with no one coming back on the line. 

After 2 hours of phone time .........................  Still NO resolution ........  AGAIN!!!    Don't know how you people expect to stay in business.