Telkom charges your extra without you even knowing

Telkom has been *****ing my money now for the last 5 months every month they debit order R500 rand extra of my account and they always tell me its my spend limmit. Now ive gone into the store now 5 times now in the last three months and made that limmit zero only to see that deduction again. So i tested them i took all my contracts sim cards out and put them asside so they cant use any data or calls only to find out ive been charged that extra R500 again worse mobile network to use will not recommend this to anyone