Hopeless support on enquiring about an e-voucher

Bought a R500 dischem e-voucher along with 2 others and when I tried to use the R500 it said the voucher had already been redeemed. I called the callcenter who told me they'd investigate and get back to me as I wanted to know when and where it was redeemed. No response. I then emailed *** who responded to me 4 days ago saying the ebucks shop department will contact me. Nobody has contacted me. Really pathetic service and I'd like to know what happened to that R500.00.