No receipt no guarantee

I bought a Copper Chef about a year ago, now the pan is not working like it should and it seems the non stick counting is not working. When I use the pan the food is getting stuck to the pan. I took the pan to Home Mark on 09/02/2019 to have it fixed or replaced seeing that the pan has a life time guarantee.

After two months they informed me that they will not be able to fix nor replace the item. When I looked on the internet for Copper Chef I saw that they only give you a guarantee if you have the original proof of purchase......What? How do they expect me to have a til slip for more than a year ago. In any case the till slips turn black after a couple of month......I m so disappointed in this product and even more it the stores that sell them.....So please if you want to buy a copper chef make sure you photo copy the receipt and keep it in a safe place.