Unhappy customer

Gert installed our invertor and a few months later we started experience problems with it. It is faulty and we contacted Gert as the equipment is under warranty. We have called Gert numerous times and if he does take the call, he promises to come out to look at the invertor. We have been calling him since November 2023 and now almost a year later later, he still has not honored his promises of coming out to check the invertor. We have also sent him numerous messages and had no response. We have invested a lot of money in the system and now have absolutely no after service at all. We will also have to approach the ombudsman as others have in this case if he does not honor his service