Failed Service by FNB

I am so disgusted with the service I received from FNB, I mistakenly made a payment to the wrong account and have been going to the bank several occasions with no assistance. I was advised to fill in a formal with no success or any attempts of recovering my money, been taken pillar to post and I am not pleased with such service. I want my money back and think it's only fair for a refund to be conducted.