Poor Service @ Toyota

SA/ Half Way Toyota Ottery I had a bad experience it's been two months now my Car is still on them.. I don't know where to go/what to do I'm only Paying an instalment of the Car that is Parked @ Toyota please guys any help what to Do? It's only been 6 month a brand new Car was Leaking a Gear Box..I was a first owner now it Takes them years to Fix it...and that Car is for Business now I'm loosing a Lot I'm Only Paying the Bank with no Car any help guys I'm LOST where to Complain...