mysterious amounts on my account

My edgars account was 100 rand in credit, over the last 2 months I noticed that a payment of R39.50 goes of my account and the description is Principal Debt Adjustment, what is this and when did I ever apply for something like this ??? I emailed the accounts department on the 15/01/2015 at 3:19pm and to date I have had no response, instead edgars sends me another statement with the same debits going off, so there goes my R100 credit..... This is ridiculous that i get charged this every month , if this is the case I am going to close my edgars account and I would advise the public out there that has egdars accounts to check them properly. <br> I suppose load shedding will be there excuse...