Why does ATT provide the worst service imaginable?

Worst service EVER!!!! SHAMEFUL ATT!!
I'm a customer for over 50 years - one of my lines is down. I have emphasized that owing to the role of this line - it's repair is an URGENT MATTER!!!! I am not exaggerating -,I have clarified over and over with ATT - and ATT's staggeringly incompetent/bureaucratically indifferent/robotic repair service can't get its act together to repair it. Numerous errors on ATT's part - would be comic were this not tragic. Pathetic!! - latest is "appointment" to come and fix line today. No one called or came despite about 6 calls to the so-called "customer service center" today. I took 1/2 away from work but "who cares!" Now 40 min on hold waiting for "expedited service" and no one picks up....(although "we value your call..". Can't make this up!) A frustrating day totally wasted and the line remains down. SHAME SHAME SHAME!!