AT&T is throttling my internet

Yesterday I did a speed test...0.0 download, and 0.3 upload. I cannot play a video, and today I can't get my gmail.

Day before yesterday, I called because my internet kept going from out to limited, and had no internet for most of the day.

They do something every now and again, and use the time to promote 'uverse' which I am not interested in.

Does anyone know who I can call in regards to this problem? I'm afraid to call their regular numbers, as that is what got me into this mess, and my gmail is now useless.