Hello,
Sorry about the trouble. If you have your device connected via adb, you could also try running this command to check the current charge rate-
adb shell cat /sys/class/power_supply/battery/current_now
If the value is negative, then I believe that would indicate that the device is net losing charge. You can confirm with
adb shell cat /sys/class/power_supply/battery/status
which will output charging or discharging.
You'll need to connect adb over wifi to retain access to the usb port to try different chargers. Here are instructions to connect adb over wifi-
https://developer.android.com/tools/adb#wireless
Best,
Adam