Hey, so this iphone 7 that I had for the last year doesnt show any signals on charge except for this one time when it actually did charge and power-on. Eventually, it went flat and continued not charging. Prior to this, i took it into a local cellphone repairer. He tested the battery and said that it is alive and that it would most likely be really difficult to fix. Im trying to figure out if it can resolved as it did work once without any professional help.