unreliable, untrustworthy mobile mechanics

I called them because they advertised as a mobile auto service company (even though they also have a workshop in Jhb). Initially they were on time, did a thorough job, presented sales slips when buying a part, indicated in e-mail the next visit. Although I always paid them on time, they became unreliable, no longer answered phone calls or e-mails, started overcharging, did not finish the job but refused to indicate when they will come to finish it even when they knew that I have no other transport and needed to go shopping. Beware of mobile mechanics whenever a particular job cannot be finished in one day. Especially when your car is partially disassembled, or when they take some parts with them. Most of them are technically good but totally untrustworthy on the business side..