Business ProfileforMaster Auto Care Center

My father took my scion in for a check up early Nov because the engine light had turned on. When I came to pick up my car, the mechanic, Alejandro stated that the problem had something to do with my coils. He replaced all 4 coils with new ones. After driving my car for a week, my car began to shake and the check engine light turned on. The problem persisted resulting in me having to take my car in 3 more times, with Alejandro stating that it "might" be the coils or the spark plugs, etc. He then asked me to pay him $50 for his time, which I argued that I shouldn't be obligated to since he never fixed the problem. He got really defensive and stated, "Forget it, you don't have to pay me!" The weird thing about it as that he kept getting defensive when I would arrive to pick my car up and ask, "What problem did we find?" and brushing me off, he'd reply, "It was just the coils." And I reply, "The coils again? What happened the first time?" He mentions that it isn't his fault if the coils he gets aren't good coils, especially since he purchases them from a third party like a junkyard. We paid him over $400 to fix the problem, but is getting highly defensive when asked in detail why these coils are failing us so soon. With my busy mom working schedule and having to go back and forth to this shop about 4x, my patience is about done. I just came from picking up my car and I pray that I do NOT have to go back there. It was the worst experience, the auto shop should not be open, and I do not trust Alejandro in the business he runs. I believe he is trying to rob people of their money buying cheap parts only to find out they are not good quality, then blaming others when he doesn't get away with it. PLEASE help!