Do not do business with these guys

I bought a house in 2013 and Plug Top Electrical did the C.O.C. at that time for the house. A little more than a year further I am selling the house again and get them to do the certificate again. Now he is full of stories that there is a toilet and a shower where there were nothing before and quotes me extra to fix these cables ect. There were also no electricity in the garage, and I myself installed some plug points and lights, which I specifically ask him to remove. Now he refuses to do anything if he cant confirm from the previous owner, which is currently living in Australia, about the extra bathroom which he overlooked the first time. I ask him to contact the sales agent and she can confirm about this, but he refuses. There is also a whole lot of earth continuity problems which he approved the first time. He is a ***** and I personally will not do business with them again!