Online purchase cancelled

I've made an online purchase last night and to my amazement I saw it was cancelled. Today I called their customer service line to find out why it was cancelled and they could not give me a reason. I used a voucher to make to purchase and the voucher and now the voucher does not work anymore. I was transfered to their bank matching department and no one anwered. The level of service recieved is poor and I still dont know how I will get refunded my money back or get them to just reopen my order!