Then sell the phone and get an apple phone. You have the solution in your hands but instead of fixing the problem you are blaming others. Stop Complaining take action. Sell your phone and get a non chinese UI. 

Have you tried to switch on airplane mode and then switch it off. Basically clearing the network stack might help with this issue.

Installation is stuck ?

Share a full screenshot of software info page of your device

I think it is only available for ultra devices. Plus and normal devices have not got the update.