Spending my money without consent

The sales side of Auric Auto are great to deal with but find somewhere else to get your BMW serviced. On a recent visit with my vehicle they spent over R12000 without any consent on my side. When I refused to pay I was escorted to the dealer principal's office (Matthew James) for a "discussion". It was very clear that I wasn't getting my keys back without presenting my credit card. In fact they threatened to "undo" the repair if I didn't pay, even though they accepted their breakdown of communication as the source of the problem. They didn't need to worry about undoing it as the "fix" that they outsourced didn't solve the problem that I took it in for anyway. After 4 weeks of haggling there's no sign of an apology or refund - just excuses. Very disappointing for one of the top vehicle brands.