This wouldn't surprise me at all. I ran into the same issue with AT&T during the switch from 3G to 4G. Suddenly, signal at my house went to absolute crap. Couldn't make or get calls. Texts would never send, texts would arrive in a random burst overnight.

Repeated visits to the AT&T store to complain were met with them pulling up a google maps like coverage map and saying "Nope see you have fine coverage at your house, go away please."