Dissapointed

I have been paying personal loan to fnb.They have helped me a lot I must say. I settled the amount 2 weeks ago and on my Profile it has been showing that i am owing Zero Balance finally.Today they took again same amount they normally deduct monthly.I am so shocked and worried if this will ever come to an End.I have so many problems that needs money,not only fnb,I have asked 2 different consultants.They said this amount they took today is interest.My question is,is the interest shoud be the exact amount that i pay month to month?Is there anything i should know?I am so not satisfied with the response i have received let alone attitude towards the 2 ladies i spoke to. Well done to the guy that i have spoken to with regards to another problem i have had on this same day.

I need an explanation,why are not given all this infomration on the APP,or even on internet banking where our personal stuff is all showing.Why this balance has to be a secret and taken away even from the Client.I am sitting again for sure fnb will debit again next month if how much and till when i do not kno.