Double debit with no response

I opened an account with Teljoy in January, had to make an upfront payment of R259.00 before delivery would be issued. I paid the amount via EFT and had received conformation from Thapelo the sales consultant that helped me. My delivery was issued and received. Now they dopuble debited me on my bank account claiming that payment was never received and is not reflecting on their system. I have waited 3 days for a response and still nothing.