Sealey Posturepedic Bad quality and warranty and guarantee are disregarded

A terrible mattress! I've had back surgery and was forced to invest in what I thought was a good mattress. So I bought a Sealey base and mattress set, for around R11000. The price hurt, but all the guarantees and warrantees reassured us that we had bought wisely. 3 months in and the mattress has collapsed. Sealey sent someone with a piece of string to say the mattress is fine when you can clearly see the dips. I am in constant pain, can't sleep and can barely walk, all thanks to this terrible bed! I am bitterly disappointed in my mattress and base set, and will never buy from them again, and will earn others that a guarantee and warranty men nothing to them!