No responses to cancelation of purchase

On 2 December I purchased a voucher for a photo book on Printstagram. I tried using it on 7 December on the Printstagram website but it said the voucher was not valid. I tried calling both Printstagram and Groupon but both numbers do not seem to work. I sent a cancelation email to Groupon on 7 December as per their cancelation policy which allows 7 working days to cancel, no response. I followed on 10 December and again on 14 December. I also tried calling with no luck.<br> <br> I have used Groupon before with no issues but this is the last time.