Looking Better Cell Phone Coverage

My name is Jerry [Edited: "Personal Information"].  Customer account #[Edited: "Personal Information"].  I have been an Xfinity cell customer for years and internet/TV customer for even more years (customer account #[Edited: "Personal Information"]).  We have 2 phones on our account and both phones are performing the same.

I have been experiencing declining cell phone reception.  When first moving to this new location a couple years ago, [Edited: "Personal Information"], our coverage was not good but tolerable.  However, in the past few months our internet coverage only shows one bar (dot) out of the 4 bar strength.  Sometimes it goes into SOS mode.  I reboot the phone and most of the time I get back to one bar but never more. 

We are experiencing lost calls or no response when calling.  

I realize that Xfinity uses Verizon's cell towers for coverage.  Is there any way of increasing the cell phone reception?  Back when we I was employed and using AT&T, we had this problem of weak area coverage.  AT&T installed a repeater antenna in that area and our reception (along with other AT&T customers) came way up and was never a problem after that.  Can Xfinity provide a repeater antenna or anything to nearby tall buildings in order to increase coverage strength?  

I would prefer to stay with Xfinity but this is becoming more and more of a problem so long term I do not know if we can stay with Xfinity.  

So basic question:  Can anything be done about this?

FYI:  Our WiFi coverage is strong always at highest reception.