Data throttling Blackberry - Vodacom data bundle

On 25 February I bought 1 GB data as well as BIS for my Blackberry 9300. The APN settings are enabled, with APN \internet\". I have used 400 MB of data with no problem until today. <br> <br> I am being throttled as if my limit of data on BIS has been exceeded. How is it possible to be throttled on data when I am using the Vodacom APN to access the internet?!? <br> <br> This defeats the whole purpose of buying additional data from Vodacom - if I am going to be throttled regardless, I would be better off not buying the data bundle."