BAD service from Fodacom

BAD serves from Vodacom. Vodacom contact to offer a modem for R150 pm 5G. The sales lady said I will only pay end August. I asked that she phone me back later. She phoned me back and I asked for a better deal. She offered 10 G for R200 p.m. Payment due end August and only the amount that I used for July plus full amount for August. I asked if there was any other charges. Her answer was NO. Today Vodacom deducted R187 from my bank account without my permission. The bank will dishonor the payment and charge me about R120+. This is not the first time that Vodacom say one thing and do not deliver, This service is unacceptable . Now they damaged my credit record, and who will pay the R187 and bank fees?