Pathetic service and a bunch of *******!

I bought a bed in August 2016. January 2018 I contacted them to tell them that the mattress has sunken in. I bought the one that takes extra weight and has a 20 year warranty! The sales guy assured me if anything happens we are covered for 20 years. After contacting them they said that they will collect it and take it go suppliers and have it back the same day. Well after waiting for days they eventually collected. Only to phone me and tell me they cannot work on it as it has a few stains on it. So there's nothing they can do to help me. It was a few marks as I have a toddler and no one ever mentioned this policy. The manager I spoke to Marius only said sorry that no one told me about this policy but that's it. When I asked them where these terms and conditions were they couldn't answer me. A few stains has absolutely nothing to do with the bad quality of the mattress!!! Now I have a less than 2 year old bed I have to dump and buy a new one because they refuse to help me. I will not be leaving it here because telling someone it's standard practice on an item that is not bought every day is absolutely ridiculous when I never signed anything to say I agree and understand their fine print!