I need help please

Hello Peter I'm Michael chuba makuwa from Germiston,in 2017 August I decided to buy a car , but I went to Alberton sales car or garage and I found a BMW 320i and the dealer told me that the car is parked the from the person who they know him and they don't sell it but they gave me the contact numbers for the owner than I called him until he arrives and I spoke with him n hi wanted the 60,000 but I negotiated until to 55,000 , than we went to the bank to transfer the money but Bank told us that the money will appear in his account after 3 days,but the guy said he will keep tpapars or the car certificate until the money appears to his account and I took the car with me but after 3day the guy started to ignore my calls n block my calls until today I can't drive the car and the car is still in his name please help. ********** 630