Unauthorised charges

On Saturda 21 July 2018 I went to Auto Fame (who sell car) with the intrest to buy a car. I saw the car but not having anyrequired documents of myself by that. I was told by mr Mark of Auto fame to leave a refundable some of R5000.00 for them not to sell the car to the next buers. I gave them the money. I signed a form. On Monday 23 July I went to the bank for some oher issues and I found out that I was elisted on credit Beuro. I told them tha I cant carry on with the purchase becausse of these developments. Mark told me tha I was going to get the refund on Wednesday 01 of August 2018. On Tuesday I received notification of R4000.00 from my bank to my phone. Iemmidiately phoned Mark. He told me its their plicy, I asked him why didnt they told me before giving them the money so I can make choices. He promised to send me yhe form. I find iit unappropriate forr me to do so and I feld rbed my money buy them.. I request your intervention in this matter. I feel like they had to make me know about their charges before I made any payment to them.