Few things may happened:
1) Insufficient refrigerant - simple, just top up. Check for leakage
2) Choked refrigerant pipe - unlikely and can be checked easily and just replaced the section which are choked
3) Spoiled invertor (motor) - Good game - can go buy a new compressor or get whole new system.
4) IC board spoiled - possible, just replace new IC board.
We cannot advise you on how much the cost from Mit or outside serviceman. Its all up to you.
Look like the best worst scenario is to replace the Ic board.
Top up refrigerant will never solve the problem and just like sweep under the floor and changing the compressor could be very costly