Not giving 2 gb insentive promised

The Vodacom Cancellations department promised me a 2gb incentive when i upgraded - I am not getting it. I have now phone Vodacom 8 times, no one seems to help. My last call I asked to speak to Manager, I was put through to a manager, but after waiting on the call for a long time, the person who received my call was not a manager. This person had no idea what was going on and redirected me again to the call center and I had to wait in the call queue again.

I don't know what to do anymore. I have tried everything I can think off. In the mean time I have to buy data and it costs me money. I phone the cancellation department, but they but the phone down in my ear.

Is there maybe someone at Vodacom who can help?