ATT lying about the offer/promotion on my internet/home phone plan.

My promotion will be over by the end on September, so i called in early September to ask for another promotion. Prior to that I did shop arround with Comcast and they offered me better internet speed with same price. So you guys transferred me to Retention Dept., they was really nice to offered me double speed for internet, same home phone service and $5 discount for whatever i was paying monthly (which is $58 after taxes).

Its just beginning, since then i had to called in every single month to get a discount because they never apply a new promotion to my account, and the bill jumped up to 64,xx after taxes, it even worst than before.

First time they gave me $10 off for the first month (September), but i had to answered bunch of questions, keep going and going, they even promised that i do not need to contact ATT again for this trouble. But you know what, same thing happened again on October, and after bunch of questions asked, an hour on phone/chat they only can get me a $5 discount, which came up to $58,xx , and still another promised from ATT's agent " you dont need to worry, we already took care of the matter, no need to call in again, discount will be applied on you account from now on"

So November is here, another bill, another problem, so guess what, i had to chat/call again, but seem like this time no one care about my problem. Chatted online they said no more promotion, so you have to pay full bill which is $64,xx. Called in again for Retention Dept. to find out whats going on, then someone told me they already applied promotion on my account, thats why i have to pay $64,xx . Because i upgraded to better phone plan (honestly i dont even use home phone). I explained what was happened in September, and she (someone from Retention Dept.) told me " thank you for being ATT customer for long time, but you have your choice to leave if there is better offer from other company " . Speechless .

So now what, can someone lighten me up please. And yes they alway ask for my number to call back in case it drops, but guess what happened, they never call, so every time to contact ATT, it must go thought chat and phone, and alway take more than an hour to fix 1 single problem created by someone who lied to me about the promotion.

Its a long post, i also have all the screenshot from previous chatted online to prove that ATT's agent was lying to me. Not sure how to post it here.