Why won’t you cheddar melt c*****?

I used to think c***** had the best quality but I am sadly disappointed.I buy sliced cheese weekly however the taste and thickness has greatly reduced over the years as well as the melting ability.its like eating plastic.I was most disappointed today when I purchased the 900g cheddar block to use in a recipe for a dinner party and it refused to melt.this is not processed cheese but proper cheddar and it sits like burnt wax on top of my meal