Bad service

I'm not happy with the way this cellular service is operating. I won vouchers for the Voda bucks but still not been sent, its been 3 weeks now and they telling me about the investigation. Screen shots were sent and everything but nothing on their side it's just excuses on top of excuses. Can they refund me my Voda bucks then keep their vouchers. They have a horrible customer service I fact they are ****s