Refund of overpayment

I placed an advert on Autotrader for a vehicle. When it came to making payment I got the error that there was a system problem with my payment and it did not go through. I tried again and made another payment. I got the same \system error"so I made a third payment. Same error. Fourth time around I phoned the call centre who told me that my payments had not gone through due to a problem with \""THEIR\"" system. A few days later all FOUR transactions were debited from my account and my ad had JUST and only then been published. I immediately requested a refund on all of my overpayment transactions to then get a \""run-around\"" fromthere onwards. Staff off sick"