VERY UNHAPPY - NEED TO CANCEL URGENTLY

My heart is extremely sore..... When I started dealing with Rental Buddies I app**** for a double bed and told them that I will pay the R1000 after the 24months to buy the bed and I have taken a single later that year as well. I have tried SINCE NOVEMBER last year sending several emails and several whatsapps and phone calls to assist me that i want to stop paying the R359 as I reached my 24 months last year already..... You guys are stilllllllllll deducting every month, which i feel is unfair as I reached the end of the contract and want to stop it since last year and NOBODY wants to assist me!!!!!! What do I do as I dont want to stop the debit order and get into trouble BUT how long do I still have to pay as this is going for 36 months now......