Impossible to cancel an order.

I placed an order on Tuesday 10 August with PC Link Computers, I needed the item by the weekend, or at least the next Monday. By the weekend I had no feedback as to whether the item had even been processed or dispatched. I then had to purchase the item from a store as I needed it for the following week. I then mailed support on Saturday morning to cancel the order. I got a reply on Monday that said I need to send a new email to the same email address to cancel it, so I did. I then got a reply saying I need to send a new email to a different email address to cancel the order, which I did. Then on Wednesday morning I got a mail saying my order has been handed over to the courier. I just want the order cancelled and to be refunded.