Vodacom "free data bundle" impossible to cancel

In February I "upgraded" "my daughter's cell package to a cheaper one as we had finished paying for her handset.

In the process we were given a 3-month "promotional data bundle" we had to cancel after the first 3 months were over.

I have tried since then to do this, and have had this "done" in-store as well as via various call centre operators on at least 3 occasions.

However, every month the charge is back on my statement again - it is costing me R200 per month and it IMPOSSIBLE to remove from my account!!!!