Delayed customer service and unmet promises

I contacted Groupon via e-mail and telephonically on the 2nd February to return a voucher I had purchased. They promised me my refund within 3-5 working days, which I understood, they then sent a further mail to me stating there may be some delays, and that I should expect it within the next 5- 7 working days. A consultant got in contact with me last week to confirm the type of account I have, and I confirmed politely, it is now 2 weeks later and still no refund. I mailed them on Friday to confirm and still no response. I have made many purchases on groupon and have referred people to this facility and if this is the treatment I get, I will certainly not be using this facility. I would like my refund paid back to me within the next 24 - 48 hours, and I would like an e-mail confirmation confirming this has been done!