Data purchased not received

I purchased 500mb data from Vodacom at 24:00 Friday night. I got a sms saying that the data was loaded.I still have not received it.I have photos of my phone where one can see that it has not been added. I complained on their FB page as there were many more with the same problem. They contacted me & I asked them to investigate it & seeing that I had the proof I asked them to allocated the data to my plan.I also asked them for a full breakdown on my May &June data as I knew it happened then as well, I would get a sms saying that my data has run out, I would immediately purchase data, switched my phone to airplane mode & switch it on again to ensure that I do not use extra data.I would then wait until I get an sms stating that my bundle has been loaded. I then received a bill for June where I was charged for additional data for 4 days in a row where I specifically know I did purchase data & was not without data for more than a few seconds.The feedback I received from them was a sheet with my itamised billing & telling me how to manage my data.They did not investigate anything I asked for.Now they ignore me and have removed my message on FB & blocked me.Please help me.