Data bought last night and no data appeared - bought 3 times in 10 minutes

Last night I bought 100MB of data, I had not been online and checked the balance and it said I had 7 left which is impossible in 2 minutes when I had not used it, I then went and bought another 100MB and again I received an SMS saying I had 100MB but went to check and balance was then 0. For the last time I downloaded another 100MB and it went through this quickly. I dont run apps in the background and was not using the internet, this is absolutely disgusting that I had to pay R 87 and it was used up in 10 minutes. I took screenshots of everything to prove it to Vodacom. I am constantly having issues which is why I cut my contract but now I am thinking of leaving Vodacom due to this happening as I feel like my money just gets taken and there is never any value in this service provider.