Misleading

I have been completely misled by this company. I agreed to a contract for R99/month for a router that can fit on my Keyring(which was BS!) The contract has been cancelled as they agreed that the sales person misled me. This morning I see a debit order has gone through on my account! I want this reversed ASAP!!!! As the salespeson also advised that the 1st month will be free and that no debit order will go through until end of May. If i do not get a response today, I will be seeking legal advise, as this is completely unacceptable business practice!