Unfair blacklisting

<div>I app**** for a contract phone from the above named company,to my dismay,the phone only worked for 4days then ink started drooping from it. I could no longer used it.i then called the company to report the problem. I was told that the courrier would come and collect it. Indeed they did.i then sent a WhatsApp msg. to cacell the contract.they never got back to me but,I'm surprised to find out I'm in arreas. How can I pay for an item I do not have? Pls help</div>