XMG3927-B50A - Features Disabled

KCOM (Kingston Communication) ISP have recently provided a new router XMG3927-B50A.
Many user features including User account creation, Firmware upgrade have been removed from the router settings. Also, in the USB setting once I connect the NAS drive they have their own user account KCOMengineering which can access the drive. I can not add new users as my default it takes me back to the main screen. Whilst I have concerns about my ISP been able to access my private information, my main concern is I can not remove any of the lockdown features they have implemented to this device. I am told that they can not offer support and I should purchase a OEM router should I want to access the more complex side of the router (Day to day operations for me) …. 
Resetting the device to factory does not remove any features. 
Any suggestions how to Flash/Remove Firmware/Update or restore to a true OEM ?

Looking for some guidance …. 


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