Disappearing data

I recently upgraded my account/contact for the 3 time and they confirmed that i would receive 10 gig every month for the first 3 months.first month everything went well then on the second month 2 April i still had 14 gig of data available when i checked balance.On the 8 i checked again and noticed the 10 gig is gone so i checked my usage and it confirmed that i only used 2 gig so where did the other 10+ gig go.I contacted Telkom and they said the data is still available.I then checked my balances but does not appear on my online balance,message balance or app balance.I have always been a loyal and good paying customer but this is very poor.