Connection loss IPhone 7 plus

I have had the IPhone 7 four days. My service is AT&T. The connectivity problems are very real. I lose service periodically and it comes back maybe 5 seconds later. Apple replaced my phone but the same problems are occurring on the new device. Is there a fix in the works? I have taken screen shots to document the problem. The Apple Store I was in today didn't have an answer for me. The problem is very real and I give this IPhone 7 a grade of F unless apple and AT&T resolve the problem