FNB t refuse to refund my money

I have open FNB account and they linked all my old closed account into my new profile I could understand what was the logic behind that. I mistakenly transferred money into my close Credit i have since requested the refund since from last week without anyluck or any help from the parties concern i regret why i have choose FNB out of all the other bank they claim that we are valued customer, on my side i dont see that, They are only good to inconvenience customers without feeling sorry. Can pleas FNB refund me back and De-link all the account that are no longer active im really disappointed with FNB, Or my God I regret why did i open the account with this bank,