Horrible network

I purchased 4 phones back in October And have been receiving error messages every day that says no network available emergency calls also Messages expired or unavailable. I went back into the store and they told me they needed to update some features on the phone and it should work properly after that. Gave it at least a week. Still the same issues the company decided they wanted to send out new SIM cards recieved them and that didnt work either. They've reset my phone and updated apps a million times and I'm still receiving the same era message. Instead of taking the phones back they are forcing me to keep them even though the network does not work and I only have 2 single bars I've taken the phones to the phone store and have them put on the machine to find out if it was something wrong with the devices and there was nothing wrong with the devices. I've been back to the store in regards to the same error messages And all the phone representatives and the store representatives. Do it string you along to make you keep the phones no one is worried about customer satisfaction. This is a sad company to have mobile service with. No one wants to help with the horrible network but they are willing to take your money every moth even tho you are not satisfied. All I want is to return the phones back to the company because the network did not work. Why keep paying for horrible service.