They are *********** and i am done with them

I have an a loan with FNB in which i called them on the 12th of the month to make a an offer for a settlement . I agreed to settle in 3 months . In which i made an arrangement for them to start deducting on the 25th of this month . To my surprise they deducted on the 16th i called in to tell them they made a mistake they must do a refund . I called on the 18th they said my money will be in my account within 48hours . When 48hours passed i called them again they said i must provide proof of that the money wasnt my salary . FNB traet people like trash why didnt you communicate with me when i called on the 18th i am not stupid to make an arrangement for the 25th not knowing they wont will be money in my account . As soon as i pay tis loan am done with FNB you just not competent >