My phone model no. M31 is. The temperature is getting higher. There is no telephone from wah wah. Took it to the service center and showed it they changed the charging panel but even after that the problem is the same.

My phone is not charging in fast charging mode. After turning off the fast charging mode, the phone is charging slowly but in fast charging it is able to charge 1 to 2 percent in 15 minutes. Please tell the reason for this.