Poor reception

I have 4 XM phones for about 3 years never had a single issue, but in the last 2 months cell service is reduced to 1 bar if I’m lucky, my neighbor who have Verizon also having same issues,   But there is no one to reach out too? Or no signal booster for in home? We replaced the 1 cell phone with new one since we were told it was old , new phone is now the worst of the lot, there a cell tower issue, but XM can fix this or get who ever needs to look at this fixed,  we can not have great service for 3 years and all of a sudden horrible service.. needs to be fixed