Arnica Refused Warranty Claim for Kitchen Cooker Due to Unreasonable Liquid Damage

I have been using my Arnica cooker for two years now, and it includes a three-year warranty. I sent the product for repair under warranty when it broke down, but they insisted it had liquid damage and requested a fee. This explanation is unclear to me. The cooker is made for kitchen use, so it's reasonable to expect it to withstand typical kitchen conditions. I definitely didn't submerge it in water, but they still used that as a reason to charge me. It seems like they are only trying to find excuses to not fulfil the warranty. I feel disappointed with Arnica, and I'm not happy with the way this situation was managed.