Vodacom
Loaded BIS last week but phone says "no data"

I loaded BIS about a week ago and it worked for a while but for the past few days my phone has been saying I've run out of data. I can't go on the internet, WhatsApp or BBM! Nothing works! I've called the call center 7-8 times and they've given me instructions that have NOT solved the problem!! I'M PAYING FOR A SERVICE THAT I AM NOT RECEIVING!!! The same thing happened last month about a week before my BIS expired. I tried to have it resolved but it still didn't work. Once the BIS expired I renewed it and it worked for a few days and the problem returned! Today I called the call center and was put on hold for 15 minutes so I just had to hang up! PLEASE HELP!