Won't accept responsibility to see job through

In Nov. 2015 we hired Francois Rademan to issue an Electrical Compliance Certificate on a property that we're busy selling. He arrived at the property, found a minor fault, repaired it at an additional charge and off he went. The attorney received the ECC soon thereafter. The buyer of the property has taken occupancy recently, although the property is not registered in her name yet. She's been complaining for a while that the switches keep tripping out and that \sparks are coming out of the electrical board when she switches things on""; so he agreed to go back and fix it - that was 6 days ago! Since then I've sent him numerous messages; but he kept ignoring me. When I finally asked him to please respond to my messages; because I can see that he's read them;he told me to find another electrician! The buyer is holding registration back until all is sorted and Francois is responsible for the delay."""