Faulty Parts

I have bought a starter for my Golf tena city car from this branch and it was faulty. I returned it and they issued me another one. However, this starter is also broken. As I wanted to return it, they said I had to buy a new one first and then they will claim for the faulty one's money back. I don't have the money to play around like this. I must now buy a new one again and wait a month for the reclaimed money. My car is standing now and I have no means of getting around. I am a pensioner.