Bad insurance company Nedbank

Bad insurance company have an home owner insurance with them. I have log a claim regarding my gyser not heating up they send the plumber than he said its an element and he change it I paid the access. Then after two weeks same problem gyser not heating up the water I call them they send the plumber now he said it a thermostat but I need to pay another access I said to him it's doing the same thing it was doing so you need to use the same claim. When I call the Nedbank insurance they don't assist they keep on saying my line it's bad they will contact me but the don't.