On March 12 everything worked. The next morning callers using AT&T cell service began getting busy signal when calling me. Landline and other cell service calls come through fine. I can call out to any phone. Two Sprint technicians checked my phone and said it is fine. The senior tech thought it was a network problem. Sprint checked my account and found no blocked numbers. The techs had confirmed settings on the phone weren't blocking anything. I've traveled 900 miles from the area where the problem began but still can't receive calls from AT&T cell customers. This is also true of calls from a small service provider who uses AT&T towers.
At this point people who know of the problem are texting me and I'm calling them back. That doesn't help with people who don't know about the problem and I don't know how many calls I may have missed. Plan to call Sprint again Monday. In the meantime would appreciate any help the community can provide.
BillJ45, Sounds like there may be a mixup between AT&T and Sprint, most likely having to do with your phone number in particular. It's isolated but I've seen it happen before and it can be fixed. We'd need access to your account and most likely need to submit a ticket to have it investigated. In order do so, we'd need you to send us a Private Message with your Sprint phone number, and PIN plus a link to this thread. It can take 24 - 48 hours to get a response, but we'll get on it for you.
Sprint Social Care Team
Were you ever able to find a solution to your problem? I am having the same problem. I have sprint and my son has At&T . I live in California, and it only affects people with AT&T service based in Alaska. They get a busy signal whenever they try and call me. When they come down toward me, they still can not call me. They can text me, just can't call me. I have had both AT&T and Sprint look into it, and both say they don't know.