Jag Electrical Services Unclaimed

We are not happy with the service from Jag Electrical as they were not honest with us. They used the incorrect wire in the garage. We sold our house and the electricity certificate failed due to this error. The quote from Jag Electrical did not state any wiring and now thy expect us to do the standard wiring ourselves?? It is a shame that companies like this normally get away with these errors. My next step is to contact the OMBUDSMAN for further advise on this?