Morphy Richards — Not providing service even under warranty. Concealing of Material Facts.

I, Aayush Bihani, have been using Morphy Richards Water Heater Salvo 10L Geyser. Recently my geyser tank leaked and being covered under warranty of 7years on water tank I contacted service centre. I provided them GST Invoice and Warranty Card of the product. But they deny providing me service because a paper sticker having serial no. that was sticked below the product worn out due to tank leakage being not a waterproof sticker. (Picture Enclosed)
Service centre denying me service because of a sticker when my product is under warranty, I am providing GST Invoice and Warranty card. (Picture Enclosed)
Neither the company nor the seller and not even service centre ever mentioned that the sticker would be so important to claim warranty. Why the customer has to suffer because of irresponsibility or fault of company. If the sticker was so important why didn’t the company took measures and put a waterproof sticker on a water related appliance like geyser or Why didn’t they engraved or laser printed the serial no. upon the product.