Recharge Voucher

I called Vodacom Customer Service on 5/2/2016 to report a recharge voucher that was not going through. I gave the agent the error message , serial number as well as the pin of the recharge voucher. The agent asked me to hold as he was trying to help. While holding a call came through and I ended the call with the agent. I thought he'd get back to me since I would be through to another agent if I called the customer service. After an hour or so , I tried to use the recharge voucher on anothet number and it gave the message that the voucher has been used. I called customer care the following day and he confirmed that the voucher had been used about 10mins after I called the previous day, He gave me the first digits of the number that had used the recharge of which I was unfami**** with. He then promised that they will investigate and get back y too me in 3days. After 6days I called the customer care , and I was told to go back where I had purchased the voucher as Vodacom does not investigate used recharge vouchers. I asked to speak to a supervisor, who stated that they will investigate if the number belongs to one of the agents, and if fit doesn't then they can't help me.