Ford SA shocking service

Week 13 has passed and still no help from Ford SA. Case number ********** 57 My Vehicle Sent in for a misfire 13 weeks ago and the car now has issues it did not have before it was "FIXED". The vehicle is under warranty and has 40000km on the clock. I still do not have my car back and Ford cannot tell me what the Problem is as they "do not know what else to do" in their words. I do not want these probleme with a vehicle as my wife drives it every day and I would not trust it again. Please help me!!!!!!!!!!!!!!