Harassment by FNB

I am not happy with FNB because they always send me statement saying I must pay how much on my credit number ********** ********** 29 and I will pay the amount only to receive messages later saying my account is in arrears, I don't understand why you don't send me the exact amount that I have to pay, at the end you portrait me as a bad player whilst is you guys that send me a wrong information. I don't know if you are sabotaging me intentionally because I did complain before with the service I'm getting from you. Even after I've paid the outstanding amount you said is in arrears but I still receive harassing calls from you. I need this sorted out and I need an apology because you are just messing with my credit status. I wish I never opened any accounts with your bank because you are unprofessional and have *********** staff. Please sort out this mess I need the full amount that I have to pay sent to me every month.