deeply unsatisfied customer

I took the car in for recall on the 23rd of August 2018. Thobile called me informing that the car has been put into the diagnostic machine and everything was in order except for the air bag spring. my car was due for service and since the car was in their hands, I booked the car for service and my husband dropped the car in the morning but after fetching the car, he realised that there was a problem with the gears. Today in the morning on the 24th of August 2018. when I was leaving my home, when I put the car on the first gear, it would more back to neutral and I've requested my husband to take the car back to the dealer because Wednesday the car was fine in the morning before it was taken to the dealer. the dealer is refusing to take the responsibility for the damaged in the car, instead they're quoting me for the repair of the gear box problems. I am not happy with their service at all. I am turning to your office for help. If you are unable to assist kindly inform me what other avenues I can use