Services fee with no explanation

I realised that if been charged extra R15 on my account for service i then phone the call centre just to get an understanding whats the charge for just after i pay may account the weakest response i got from the lady is that as long as there is amount due they charge me on every 7th of the new month but im not on areas or pay late then she o it might be cover for the card i asked her what's the replacement value of a new card if you lost or damage it not s****