if you are truly set on getting a diff type of phone. Stick to the role of "these phones are not allowing me service due to the issues"..
waaaaaaaaay back when VZW was just starting out i lived in a town that had a local Corp VZW store. 8 miles from that store at my house i had to go outside to use it. ...long story short they allowed me to swap to a diff device ...that didn't help. Ultimately i was allowed out of my contract without ETF due to "lack of serviceability" ...now that was over 1o years ago things may have changed now.
I'm not telling you to be dishonest but if the issues you have truly prevent you from receiving service...then run with that.