Microsoft — Lumia 640

In september of 2016, i bought two identical phones at walmart. They were locked to t-mobile, which allowed use with walmart family mobile. A few months ago, both phones refused to charge on the oem chargers. I purchased two new oem batteries, thinking that should be the solution. It was not. The problems persisted. The only way i can charge these phones is via usb. Until yesterday, that included usb-to-ac chargers. Now, they will only charge via usb to computer.in addition, they are both experiencing 'no service' more and more often. This never happened previous to the other problems. I had the carrier reset the phones. Problems persist. There is no contact info for microsoft as these are out-of-warranty. I have been unable to find anyone else who has had the same problems with this model — or any other model of ms lumia phone. My concern is that i am having the same exact problems on two identical phones — and both started having problems simultaneously. I want someone to listen to me about this, but neither ms or t-mobile is taking responsibility. There is something very strange going on...