Easy way out

Really frustrating that this company has repudiated my geyser claim. It is supposed to be under warranty but they state it is void cause there found a problem with the plumbing from their opinion. I have consulted with 2 other reputable companies and they state that there is no issue with the plumbing . Kwikot was also at my home in 2016 and that claim was approved and nothing was changed with the plumbing there after. Simply upset that they would not honour there guarantee for their inferior product.