FNB AGAIN!!REVOLVING LOAN "Facility" interest hike?

Once again FNB has proven incometeant I received a mail stating that my revolving loan has been migrated to a.. " Revolving Facility “.... What does mean.... Is it the same thing just different name.....well the call centre agent i spoke to at the time said is EXACTLY THE SAME.. And mainly I know I pay R502 on the 20th of every month... I haven't used this facility for a looooong time only this past month had an emergency...... I just want to know that I will still be paying a monthly repayment debited on the 20th of every month still correct??? ...But no i was debited R117 for interest and an additional R490 some odd. Tried to get hold your call center this morning for explanation being sent from pillar to post....to my understanding a revolving loan has a monthly debit no matter the amount I used...it's a service fee and the monthly...where does this R117 come .that's nor how it was explained....it's like having a credit card in that case...absolutely unclear..as a former employee..I would expect this complaint to be dealt with in a timely fashion. Call me!!@@