Promotional Data a Lie

On the 6th of this month I bought a 3gb on the Vodacom app under promotions if you buy with your bank card. I only use my data at work,but I've notice that I can't read or see pictures on fb and when I Googled it gave me an error. 1st I thought it was the signal but on Friday at work I had 4g signal and tried again but it gave me an error. Vodacom you increase your discounted data and calls on *123# every time when you feel like it without letting your customers known. And this month that I bought data for I have important things to do during business times,your promotional data seems to be a joke. This is the 1st time in ages that I bought data coz I only buy what's app bundles but it seems money is in the drain. I've restarted the phone several times but it really doesn't work you can log into my account, I've even took screenshots. Maybe there is people with the same proplem but now they think it's their phones,& maybe people that took there laat money. I really hope you can resolve your promotional "sale" that I had to pay to what's app only.