Superhot gyser is totally wrong

I bought their gyser in feb 2022 at K carrim. It srarted showing us flames last week when burst and we call they warrant call center on the gyser and they came as soon. The plumber cam and check it and even told me hair superhot things they do and told me they will call you so that we could come for installation. Jik jik the sent me text on my whatsapp saying your warranty for your supahot has been voided due to the installation of a 600 kpa pressure control valve which we were not told on the purchase it has no manual that gyser. So why do the wrote 5year warrant when they don't know the meaning. I feel ripped and ****ed.