BMW of Murrieta

Everytime I take my car in for a simple service it comes back with major issues that were not occuring before I brought it in. The first time I took it for a simple oil change all of a sudden I had a coolant leak, a oil leak. I asked them to replace a specific tire and they replaced the good tire and left the bad tire that had threading coming out of it. This last time I took it in for a oil change and a service recall and the day I got it back with warnings of the engine temperature being high and all of a sudden the day I retrieved it back from them my powersteering went bad and all of these other problems that totals about 12k. This is by far the WORST dealership I have ever dealt with, I should have stuck with Mercedes.