UNAUTHORIZED DOUBLE DEBIT

Im extremely upset and disappointed with the services of Fnb in regards to my personal loan, Fnb debited my acc with the full amount of R1195 and taken off aand a second debit R1195 totalling to R2390 without an arrangement. Ive been on maternity leave for 4months and just got back to work a week ago hence i did not receive a full salary, i requested 1 debit to be refunded however my refund was declined. I was willing to pay the debit end of April incl arrears but this cannot be done according to Fnb,after calling numerous times theres has been no joy, i called back and no approval passed on my 2nd request, this is so annoying and upsetting I did not give any authority for a double debit! 😡