Bad Quality Mattresses

I bought a Base & Mattress ( Sealy Bordeaux 152cm ) set on 20/3/2018 at Rochester Parkview Mall Pretoria. 8 Months into my contract ( 9/11/2018) the whole mattress collapsed in the middle, Sealy's guys came to inspect the bed 1st and then a week later they exchange the bed for me. My contract was 12 months with them, so March 2019 my contract was paid in full in beginning Nov 2019 we started realizing that the new bed is making cracking noises and the bottom part at our feet has collapsed again. So I went back to Rochester 2 weeks ago after it started to get real bad informing them about this, Sealy phoned me this morning 20/12/19 asking what is wrong with the mattress, I informed them and without any questions ( as if they new there products is ……. she said they will change it, but seeing that I bought my bed in 2018( which is not even the same one anymore ) I have to pay R 1400 or something to exchange because the guarantee expired. My issue I have is this is a new mattress that was a year old on 12/11/2019, and again is damaged but they expect me to pay for this. She went on about my guarantee is 12 months and it's expired bla bla bla, I checked my contract I signed and nowhere it stipulates anything about warranty or guarantee. So now I want to know if I changed the bed now and in 12 months time it collapsed again like the previous 2, I have to pay again for a new one, this is bulls..., I want this bed changed with no costs to me, seeing that I did not even get any proof of warranty or guarantee in my contract. It cost me R 8836.38 not little money. Either they exchange for free or I want my full amount back that I paid for this bed as it is bad quality they sell.