Top up Vodacom DATA

I only have data contracts with Vodacom , sometime I run out of data and need to top up , so I registered on there website to purchase more data, the only option I have is to pay with my credit card. So this time they had technical problems , so I phoned the call centre and were advice I cant due to technical problems I need to find other means. The big problem with this is that if I don't have any data you cant do it via internet banking and need to drive a get a top up at a Vodacom Shop where price are double the top charges on the internet and as were advice when you sign the contract . Is seams Vodacom always now have technical problems if you want to top up your data and the unskilled and uninformed and rude call centre agents cant assist, so if you run out of data you will pay double the cost to top-up , also you cant gent out of the contract before the 24 month or ells pay almost the whole fees for no services ect. The only conclusion I can make is that they advertise false information with extremely unskilled call centre agent witch cant help you with anything.