re: iPhone 7 wont seem to charge or power on

Attempt to clean out the port like the LSUtigerME says, it's incredibly common. If not plug the phone into an outlet and hold the power and volume down buttons for about 15 seconds to attempt to reset the pmc of the phone. If that doesn't work take the phone into an apple store or authorized service provider to do whats called the icc test (to measure the current going into the phone) and to see if the phone is able to turn back on.

Edit: also ensure you try multiple cables to exclude the cable as the source of the charging issues.