Always "not available" when data has run out...

For the umpteenth time, I once again had (currently still have) issues with the Vodacom online service and app. Every time I run out of data bundles and I want to add more, the service is always "an error has occurred. Please try again later". This necessarily means that I will now pay way more due to not making use of purchased data bundles, but making use of out of bundle rates. As I said, this is probably the tenth time that this is happening to me and I believe it is unfair practice and a way of making one pay more than he should. In my view this goes against a consumer's protection and rights and I will insist on this being investigated.