Why is landline repair closed on Sundays?

My mother has been with AT&T for close to thirty years. This past Friday, 3/15/2018, she moved and ported her old phone number over to her new apartment. She now has a traditional, wired landline. The tech came out on Friday to perform some work on the outside wiring and then came into her apartment to make sure everything was working fine, and it was...until Saturday afternoon. She can receive calls, but cannot make any outgoing calls. I called AT&T only to find out that the repair office is closed on Sunday (unless, of course, you have Uverse). I was instructed to call back on Monday, when the repair line is open. My mother is 87 years old and has no way of making a call. I am shocked at how AT&T treats senior citizens who are the most vulnerable among us. It is utterly disgusting. I am writing to the Attorney General's office in Florida and reporting this to the FTC as well. Shame on you!!