Sleepmasters deliver wrong bed and demad more more to exchange

I went to Sleepmasters to buy a bed cost R3299 and they convince me to open an account, i app**** and it was approve. Vanisa convince again to change the type of bed and size which was R4299, i agree but they deliver the bed, i choose first cost R3299 although they charge me R4299. I went back to the store and ask if they aware of that, i found different people every time, i went there and they telling me to bring back the bed and come with an amount of R1500 to change the bed. The bed that they gave me, i don't even use it because the springs are coming out. i went back to same month, i bought and Vanisa said, i must first pay up my account and i did but they telling me about R1500 although they gave me wrong bed.