Nedgroup double excess when it broke same day

I submitted a claim with Nedgroup for my geyser leak on the 29th, Hutton Plumbing came within 30mins, repaired, I paid excess and left. The night of the 29th I ran bath water and it was cold, went to the geyser and saw they turned the switch at the geyser off so I turned it on. As I turned it on I noticed the power tripped. I put the main on and everything was fine. The next morning I switched everything off and I went away. I got home last night, turned the geyser on and still keeps tripping only this time the main power won't go on unless my geyser switch is off. Called the plumbing company and they said I have to submit another claim and pay excess... Why must I pay another excess when they worked on it and ever since has done this?? If there were two issues, being the experts they should have replaced both things or everything that was wrong. What if they blew something while working? Now the new plumbers are coming tomorrow and need excess before they repair. This is nonsense and I want to fight this. How unfair