Client Service at its worst from SA Taxi

I recently bought a second hand Toyota Quantum from SA Taxi. The vehicle was bought in February 2016 and this is the 3rd time that I am sending it back for mechanical fault. On Monday 25 April 2016 they came to collect my taxi from Bree Taxi rank were it was standing not moving because when the driver put the key to the ignition....suddenly it did nt want to start. Now they are telling me that the key that came with the car is not the key that they gave me initially. I was given 2 new set of door keys and one set with one door key and the ignition key. The ignition key doesn't have the Toyota name...now I am told that I could have swop the keys I don't know how...my claim now is been declined from warranty....i have confirmed with the sales man and he told me that even at their ware house they have lots of spare ignition keys with no Toyota name on. I am very disappointed as I thought they understand the nature a taxi business better than anyone. I need urgent help as my taxi is standing the at Taxi mart with no one wanting to take a responsibility for the key....my business is standing and now I have to pay the instalment due next week. Please help..my name is Daphne Mabaso cell:***