No Business Ethics

Have a brand new 2019 BMW 120 series. Check with BMW to fit a tow bar for my vehicle. After confirmation and receipt of an official quote from their Pinetown branch, they requested that I must pay them first before they can order, which I did R17,003.00. After a week I was contacted by BMW that the part arrived. The vehicle was delivered to them. After 3 day`s I was informed that there is a delay and they await a part number for a smaller silencer from BMW Germany . In the mean time I purchase a bike trailer. After two weeks BMW informed me that the silencer is now discontinued and they will repay my money. Now I sit with a brand new BMW bike and a trailer but I cannot fit a tow bar. Other companies can fit a unit on my vehicle but BMW threaten me that I will then loose my guarantee. The same evening a sales person from BMW phone and enquire if I want to buy a new car based on what happened. What to do now? .