I'm about ready to switch to Verizon!!

Hi. First off, I've been a loyal AT&T wireless customer For 15-16 years now. I've been through many company name changes, U.S. cellular, Bell South, Cingular, AT&T, maybe more, but I have had it with being on the phone hours and hours trying to make this company understand my issues. I have bought who knows how many phones, have had who knows how many different plans, have never had my service disconnected, and have been late maybe a couple times throughout. I have four devices in service. Well three at the moment.
I downgraded my plan from 15gigs to 10gigs about 6 months ago,(I've gone up and down many times) when I did, my next bill was $100 more, which makes no sense, and of course I did not pay it. I've been on the phone with customer support for hours and hours, wasting life. Since that bill, I've been charged $5 a month late fee every month, which I will NEVER pay. I need help getting through the crap of being transferred from this person to that person and never accomplishing my goal. Can anyone tell me how to get to someone who can meet my demand of either taking all of that off of my account, or giving me a date to close my account, and switching to Verizon, who of course says that they will pay AT&T those charges if I'll switch. I need a contact other than the 1-800 customer service number or the 600 number
Thanks, and sorry to ramble on