Order canceled with **** of payment sent

I ordered an item online and followed their procedures as usual, sending them the proof of payment. A few days later I got an email from them asking to send the proof of payment, and I sent it again. After a week, I emailed their customer service, got a prompt reply, but they had still not received my proof of payment. I then sent it to the customer care person I was in contact with and the payment notification email address. The week after this was the December holidays and I knew I wouldn't get anything done. I phoned multiple times in January, and when I eventually got through they told me the order was canceled because they did not receive proof of payment. The friendly telephone operator said he would phone me back as soon as he can get hold of the finance department and find out what is going on. Weeks passed because I had my own troubles, but I phoned them again today and they still haven't sorted it out! I am yet again asked to wait for them to phone me back while they try to figure out what happened. I am highly upset, and as a student, I can't just throw R650.00 away.