"Do you guys sell the glass part on the back of the phone?"に関する回答Here is everything they sell for the XR: https://www.ifixit.com/Store/iPhone/iPho...-XR?display=list It doesn’t look like they sell the back glass.
"iPhone 7 Plus doesn’t charge"に関する回答It’s very possible it could be the battery. But there is a chance it could be the charging port also. If you’ve had problems charging the phone before (It will charge to 100%, instantly drop down to 40% after being off the charger for around 5 minutes, and then die) it’s possible it could be the battery. If when you plug in your phone and it will not show that it’s charging at all, then it’s possible it could be the charger, or the charging port. I would recommend trying a new charger before getting a charge port replacement. If you would like to replace the battery yourself here is a step-by-step tutorial, along with a new battery : iPhone 7 Plus のバッテリーの交換 iPhone 7 Plus Replacement Battery If you would like to replace the charging port yourself here is a step-by-step tutorial, along with a new charging port : iPhone 7 PlusのLightningコネクターアセンブリの交換 iPhone 7 Plus Lightning Connector Assembly If you bring it into a tech shop that can fix it for you, they should be able to “Open test” a new battery and/or a new...
"Mic and Remote hardly working"に関する回答If they are brand new apple headphones and there isn’t any physical damage on the headphones then the apple store should replace them for you. I’ve had around 4-5 pairs already. :)