Can you still take it back? Sounds like a clear case of fraud, the fault was known and not disclosed, contact your Secretary of State / DMV.

Seriously. These things will eat you alive with 4matic problems, if it isn't working properly and you paid over $2k, take it back.

It sounds like the PO disabled the system with the switch "per the manual", try turning it back on.

__________________

Gone to the dark side

- Jeff