BILLED WITH NO CONTRACT

I had contract with IBURST 750 meg USB (with Vodacom sim) for R220.00 per month only. Suddenly VODACOM started to bill us without any contract and deduct from our bank account an amount over R5000.00 in one month without any authorization. Upon enquiry at IBURST, I was told that VODACOM took away their customers. Upon enquiry at VODACOM, I was informed that according to their system, I have a uncapped account, meaning I pay what I use. I therefore have to pay, according to VODACOM. I requested a copy of the \contract on the system"April 2014"