The MMI on my 2013 Audi A6 C7 is only operating intermittently. Sometimes it will open on start up/ignition, sometimes it won't and then it will open randomly at some point during a journey, sometimes not at all and it seems to be getting worse i.e. taking longer to open - very frustrating!

The 3 button reset does not seem to work.

Any ideas how to get this fixed?