car broken again

I am not a happy customer, my husband took our BMW to the Xtreme Auto Electrical & Mechanical Repairs workshop in mitchells plain in Nov 2015 and they advised him that they will be able to fix the BMW alternator only to find out that they are not skilled to fix the alternator of a BMW and they took it to Diesel Electric (Parow), it cost us R1600 to have it fixed and we waited weeks for the alternator to be replaced on the car and for the car to be driving again, the mechanic from the Xtreme Auto Electrical & Mechanical Repairs came one Saturday and had it put back and guess what 2 months later it's broken again and now I need to spend MORE money to have it either fixed or replaced, I had the car taken to another place after we got stuck on the side of the road 2weeks ago and the mechanic confirmed that the person from Diesel Electic that worked on the alternator ******ed it all up. I want to know what's going to happen as it was supposed to be fixed the 1st time around and not me having to spend more money, I am contacting my lawyer at legal wise if I don't have an answer by Friday the 04.03.2016 and I am taking the matter to the small claims court.