Mitsubishi Outlander 2010: Why did the engine light come on?

Last year the check engine light in my 2010 Mitsubishi Outlander came on and the engine stopped while driving. Since then I have taken the car more than five times to a dealer for repair. I once even got charged for it. They had the car for a month once and when I collected it, it only took five minutes for the check engine light to come on again. They provided a hire car for last time, but nothing like mine. I took the matter to consumer affairs and they advised me to go to VCAT. I am frustrated with the lengthy delay and their poor customer service. Can you please guide me what I need to do.