Jet store refund the money for my e-gift voucher

I purchased an e-gift card for R1000 at Jet store in Carletonville town. The voucher never worked as the voucher number keeps saying it is invalid. However the balance in the voucher keeps reducing. I had tried to get help at various stores in different provinces to no help. I am just being send from pillar to post and even the explanations the call centre agents are giving me, do not make sense. All I want is my money back. R1000 is a lot of money to donate.