Inability to use data that I purchased

On 28/08 I purchased Telkom's R99 FreeMe Bundle which includes 1GB of all networks data and 500MB of social media data that I can use for Whatsapp, BBM or Instant Messaging. On the 29th, the 1GB depleted which was okay because I had been on the net all night, however I was now unable to use the 500MB. Because I thought there was a problem with my phone, I switched it off then on again but my Whatsapp messages still wouldn't go through. I then bought 150MB daily data because I wanted to check if that would work and it worked perfectly fine but after it depleted my messages wouldn't go through so I rang the call centre to be told that they will pass it on to back office so they can look at it. Now this is not the first time this has taken place, it happened in May and the lady I spoke to then told me that my data was locked. This has caused a major inconvenience as I communicate mostly using Whatsapp now I've had to buy data again and connect to wi-fi to ensure my messages go through.