Extra airtime being depleted (expensively) before data bundle

When I loaded R55 airtime this morning, I was granted R27.50 extra airtime for use within 24 hours. I also purchased a 1 gig data bundle for R49. When connecting to the internet subsequent to this, I noticed that my extra airtime balance was depleting while my data remained unused.

I contacted the call centre and was informed that the policy has always been for extra airtime to be used before data bundles. Only once the extra airtime runs out would I be able to use the data bundle.

My problem with this is as follows: I planned to use the extra airtime to make calls. If I use the internet at any point, this balanced is reduced, even though I have a data bundle. Furthermore, I am being charged out-of-bundle rates, namely R2 per mb. So after using 13.75 MBS my R27 extra airtime will be depleted, whereas if I used my data bundle I would in essence be paying R2.86 for the same amount of data. I bought the bundle with this intention.

I was told that it is not possible for this to be changed, that I must accept it as this is the way it has always been.

I am not happy about this, I feel cheated. If it is not rectified, Vodacom will lose a customer they have had for 15 years, and I will further recommend to everyone I know not to use Vodacom.