Credit given while under debt review

Good day,

I have a premier account with FNB that I mostly use to make online payments with as I prefer Visa. My son use this card to buy items online without my supervision because i deposit money into this cheque account so that he can purchase whatever it is he wants to buy then if there's no more money in the account it would just state "transaction declined, insufficient balance". For over 2 years it has been this way without any issues because I am under debt review so for obvious reasons and according to the law - the account can never be overdrawn or have an overdraft facility.

This month my account is minus R7000!!!! FNB allowed my account to go into arrears/overdraft. I never app**** for this and even if i did it would be rejected due to me being under debt review. How on earth can FNB afford me credit of R7000 while under debt review and without my consent??