Horrible Coverage in my Area while paying way too much for phones no one can use

AT&T service used to be great where I live, but now, I can barely get a signal with any of the phones on my account. Over the 5-6 years that I have had AT&T, we have had amazing coverage and have been very happy with them; however, over the past year, the coverage has disappeared almost completely while the bill has gone up. We have to walk outside to get service and there is only one spot that gets service; but even when you find that spot, if you flinch you lose coverage.

We live about 30 minutes from town, so we are out in the middle of nowhere pretty much; however, there is a tower not even 5 miles from our home, yet we can’t get service in our home, or along different routes we take to get to either town.

We are paying $238 for phones we can’t even use. I understand there is a tower we can buy and also get billed for every month for usage, but I’m not paying for it when I can switch and get better service and a lot lower bill than what I’m paying now. I can get unlimited plan from cSpire for $120 dollars where I’m paying $237 for 10 GB of data plus one iPhone on the AT&T Next plan. Is there any way to lower my bill and get better coverage in my area?

Also, my sister uses Cspire so I could get a bill credit and so could she by switching. And I also know that she has coverage anywhere, and she lives farther away from town than we do and has excellent coverage. However, I don't want to switch if I can avoid it. I've had a great experience with AT&T. Their customer service personal is always helpful and polite.