service failure

I bought a voucher on groupon two months ago for one of their service providers of which when I collected the voucher in question I didnt get what I initially purchased. It was a voucher of 2 platters of which I recieve 1 platter and their service provider **** to me that it was all in one platter of which it wasnt and I tried to contact the service provider but she never picked up my calls cos I thought it was a human m istake I have phoned groupon and reported my case they asked me to forward them with the evidence of which I did but I have never received any response from them. Groupon they are so unhelpful on this regard and they failed to investigate my case instead the wanted evidence from me why they dont do proper screening on their service providers. I have phone groupon again 3weeks ago they still never came back to me. All I need I want my money refunded that all. I cant be taken for a ride why pay for something thay I never recieved. And I feel their is no customer protection on groupon