5 Months and over 50K paid and still don't have my vehicle

After 5 months and a full payment of over 50K I still don't have my Audi S4 SA Megatronics now wants to blame Mayfair gearboxes but before the car even went to Megatronics SA they where told that the gearbox was removed by Mayfair Gearboxes and still committed to the quote given by them it's been 5 months 2 weeks ago I received the vehicle and was told the car is still in adaptive driving I drove the car home but was still skipping gears and the engine shakes vigorously when in drive the following morning we requested them to collect the vehicle as I was not happy they told us that the vehicle lost its settings and that they must start the adaptive driving from scratch as it will take 2 weeks and that they gave it over to their lawyers because we talked them bad on social media so where else must a customer complain if it's 5 months and a payment of over 50K was paid but still no vehicle if I was the one not paying I would have been charged storage fees per day but now I had to wait for 5 months and still don't have my vehicle