I don't have a Vodacom account

'm shocked to recieve SMS notifications that my bank account jas been debited by vodacom. The debit orders bounced as this os no longer the account I use for my salary. Please explain how I can be debited when I never opened even a single contract with Vodacom? I called customer care they confirmed I have a contract package with them. HOW???? Do I not need to submit my ID, Payslip and Bank Statement to open a contract? Customer Care says I must go to outlet but that's not good enuf. My credit record is on the line here.