Worst Service Ever!!

I have had bad service before, but wow Game takes the cup. I placed an order in June, the wrong item was delivered, i logged a collection and the item was collected a week later (this is after i had to follow up numerous times as to when the collection will be done and having the consultant chatting with someone in the background in their language about how they could never deliver the wrong item, i must have ordered incorrectly). I had to wait another week or 2 for the deliver and yet again the wrong item was deliver (You won't believe this, but they delivered the same item i could tell cause not only was the box open but it looked old and damaged). When i told the driver that i can't accept this he said to me i have to and will need to log another collection, which i did. It took them another 2 weeks for them to collect. Long story short, i keep getting bills and calls about how i have not paid for 2 months now (mind you they are charging me interest on these outstanding 2 months). My question is how do they expect me to pay for something that i have not received? I refuse to pay a cent till i get what i ordered and feel that it is only fair that they start billing me from the day that the correct delivery takes place.