Rude, uninformative, and disrespecful and slow service

My car was taken to CBS motor repairs in Voorbaai and has been there a month already. I am now being told the whole service was done but upon taking the car for a test drive the engine light keeps coming on and the car wont idle and they dont know and cant find the fault. They do not keep their customers updated even after promising we will phone you back and keep you updated i phoned again and was told by the mechanic i cant do my work if the customers keep phoning and i also ran out of airtime so called on whats app and was told who the .... calls on whats app. They are rude do not keep customers informed and i was then told they have to get ford to come see if they can find the problem so they dont know when i will get my car back.