Over 4,000 feet from box so TV service was pixelated

I have been an AT&T customer for at least 20 years having TV and internet.  About 1 year ago we switched to UVerse TV. Beginning in July, 2017, I began experiencing pixelating on my TVs. Technicians were dispatched on six different occasions over 5 months completing the following; changing the network interface card, changing the modem, installing new lines, and changing the card at the box. The pixelating still continued. I was finally told that I was more than 4,000 feet from the box and therefore would not be able to have UVerse TV. I therefore cancelled my service and they have charged me a $60 early termination fee. I have tried on many occasions to have this charge removed to no avail. Please help.