Motorola Solutions — moto m.. i'm complaining about update issues for my phone

Address:

Mumbai City, Maharashtra

I have a update issue with my phone moto m. It is since when i gave my phone to the official motorola gallery at orchid plaza when my microphone had got damaged. After the repairing done of my microphone i got my phone back with an update done of android 7.0.. Directly from the service centre but since that time my phone had some display issue while switching on the phone with android 7.0.. Then i complained it to them about that issue but instead of resolving it they gave me my phone back with android 6.0 again by saying that it is not supporting in ur phone even when all the moto m have officially got an android 7.0 update and it is also supporting in all the devices. So after that i used android 6.0 for about a while but then i myself tried to update to android 7.0 through wifi but then after updating my phone it was not switching on at all. So, i again had to visit the gallery and they were able to switch on my phone as before but again as before they didn't resolve my issue and gave me back by degrading to android 6.0 again...
I'm really tired of going to them again and again for the same issue and i want to use android 7.0 in my phone as i have received official update and also would like to request to know the actual problem for the issue and get it resolved.. Please help me as soon as possible...