Generator Service and Repairs

I have used this company for several household repairs - electrical repairs - good, fridges - good, Diesel Generator -overall bad. I have used them in excess of 10 times to keep repairing a diesel generator and paying several times for labour and parts including generator removal and overhaul twice at their premises. Typically repairs work for a few days at a time - the last "repair" lasted 1 day and their technician claimed it could not be fixed - after full services at their premises. I complained to the owner - Godfrey Ngwenya who promised to investigate and never heard back. I suspect that their services involved supplying second hand parts etc