very dissapointed after purchasing brand new bike

I purchased a brand new BMW S1000 RR in December 2017 and had the bike registered in January 2018 from BMW Motorrad in Centurion. I rode the bike for 3500km with the first run in service done by the same dealership. I noticed an odd noise from the engine so the bike was towed to the dealership over two weeks ago on the 9th of July 2018, they came to the conclusion that the problem is due to a manufacturing defect. The root cause of the noise is due to a gudgeon pin being loose between the piston and the rod in cylinder 3.

BMW are now repairing the bike and not giving me a new unit.

I cannot accept the same bike because it is now completely stripped and put back together. A new bike was purchased because I was aware of the speed the bike is capable of and needed peace of mind that the bike was not tampered with.

Although it was a brand new bike and the fault was caused by a manufacturing defect, I still accepted this decision and asked them to take in the bike and let me pay the balance outstanding, they said no to this as well as if they do then i am forced to take a new bike which I do want.