I transferred R200- ...

I transferred R200- airtime from my mtn pay as you go to my other mtn pay as you go Cell 065****612...I received a confirmation sms that R200- sent from 083*****9 and new balance R200-....I needed to buy data with the R200...I needed to buy data using this number...next thing I see my balance is R79- this was in a matter of seconds or 2 minutes at the most...I just need mtn to re-instate my airtime...I'm now without airtime and data...I am soo angry ...my plans are ruined.