How do I get a refund for a duplicate Payment ?

I renewed my License via the Natis Online service and received the licenses by Courier. No problem. A few days later I noticed that the amount went off my Bank twice ( duplicate payment. ) I phoned the number"Talk to us" Waiting time 89 minutes. Eventually got hold of a Call Centre Agent who advised me to send proof to ***. As expected, even after several follow-up emails, there was no response whatsoever. Went to the Local Traffic Department where I was once again advised to send an email with proof to *** I am completely at a loss now. Anybody out there with advice ?