Mattress springs came off

I bought a queen sized mattress from the in March last year and in April this year a spring came out. I logged a call from them asking to replace the mattress. They have been giving me a run around and instead of replacing my mattress they are telling me that they do not have it in stock anymore. So I have to pay R3000 more in order for me to get a new mattress. Which I cannot accept because we are not told such when purchasing their products. I’m sorry but their service is appalling. I don’t know if they would sleep on a mattress where they have to constantly worry about mattress springs poking them in their sleep. The Mattress was only comfortable for the first 3 months after that the quality deteriorated so bad that you wake up with back pains always! This is so disheartening