Car Servise City

I took my car for a major service A5 Audi, it was all good in the morning it was all good, when collected my car at Celtisridge shopping centre and paid R2795.00, while driving it, white smoke came out of the engine and exaust, when i confronted them, they were so rude as i ask them what happened, now iam sitting with the damage they caused, dont know what they did. I will open a case against them. Please assist as i want my money back for damages caused.. They dod not want to own up as to what they did