u-verse caller id number has an extra (1) in front of the (1) that precedes the area code
SO, no way can you call the number back since it has that extra 1 in front and not the entire number because of it.
Forget about adding the number (even if you knew the last digit) to your directory since you CANNOT edit the front of a phone number - just have to rekey the entire number.
I have a Sony spp-a2480 base phone and handset (they still sell them by the way).
I took my phone to the next door neighbor who has a regular at&t pnone line (copper all the way - CATW 😉 and called his number using my cell phone AND it displayed correctly.
Why does this happen with AT&T - are they trying to sell their own Phone?