Could not redeem my voucher

Good day <br> <br> Last year May 2014. I bought a groupon for a character cake and cupcakes from Cake and stuff, when I tried placing the order , I found out that the company ( cake ans stuff ) could not do my order when I needed it as the lady was in hospital.i sent a email a to groupon and then they said they could get my order done after June. My son's birthday is on the 14 June. Then I said that the voucher expires in before I can use it cause there is no ones birthday after my sons. I was told by Cake and stuff no problem we will do it when you need it even if it's after the voucher expire date. But now I'm having the problem getting hold of the company cake and stuff to get my order through. I therefore would like my full refund as I was not delivered what I was promised.