Vodacom voucher already used

On the 01/01/2015 I purchased 110 vodacom voucher from island view supermarket.On redeeming it, the message came back as already used.Since then I have been back to the retailer who told me I need to call vodacom.I called vodacom and they told me to go back to the retailer and they will reimburse the retailer.Again I went back to the retailer who told me that vodacom must sort it out.I then went into the branch (bluff ) vodacom who said I should go back to the retailer.I have paid R110 and I am disgusted that 6 weeks down the line no-one can assist me.First of all I dont understand how the voucher has already been used and the voucher was only printed on the day from a website called [URL Removed] and has been used.Have to wonder how many people are being ****** of airtime.