I have an iphone 5s and the software is ios 8.2. We have been told we live in a marginal area. It took 15 days to get a voice mail, I missed3 calls from the same contact, I miss text.. I miss a lot. And it isn't just one number.
I just got a new sim card, but does not seem to work any different.
We have a network extender, but it doesn't help either.