Offer to Purchase

I recently signed an offer to purchase at Ballito Autohaus to purchase an F30 320 M Sport BMW. This was after enquiring about the limited edition M Performance to which the salesmans response was that there is none in the country. After signing the offer to purchase and realising that we cannot get the M Performance we wanted we paid a deposit. 4 days later we found the M Performance at another BMW dealer and decided that we rather get the car we wanted considering the amount of money being spent, afert all why should we settle. Ballitto witheld R15000 of our money as a cancellation fee and to date we have enquired on the criteria used to get to the amount and have got no feedback from Ballitto. The quote we signed stated that a reasonable cancellation fee will be charged. In my opinion R15000 is not reasonable. The amazing thing thing was that we were initially treated like royalty at ballitto but today they do not have time to assist us in understanding how the amount was reached. BMW SA also refused to help saying that the matter was between the dealer and me. How disgusting.