Wrong items sent, and I returned but still shows I owe.

Hello Peter My name is khanyisile machi Can you please help me I had any issue with homechoice I return back their goods they ask me to pay ,if I told them that how am I going to pay for something that is being turned,they ask me to bring proof that says I return back the goods.so I don't have that proof because the guy who came to collect the good came with the scanning device and ask me to sign to that scanning also , please help me I can't pay for something that I d not have.