Poor and unprofessional service from standard bank

I am experiencing poor and unprofessional service from standard bank. No one wants to take responsibility on their mistakes but expect me as a client to cover their mistake by harrasing me daily with phone calls . I am sick and tired of poor services where you can not speak to a manager who can see error and take accountability on the ill information that was and is still being given by their staff from January till now 2018 April. I am being charged interest on arrears that were already settled as per arrangement. After settled the arrears I am being harassed daily with different calls and message. I have to explain to *********** staff what happened and still waiting for them to take responsibility of the charges that I paid already. I have asked them again and again to listen to the calls that they claim are recorded but no one wants to do so. I wonder if there is a real manager or customer services person who can assist to resolve and stop my harassment from this organisation that wants to blame customer for their mistakes. I would like get help from any body out their to hear my case and get standard bank of South Africa to account for their mistakes rather than continuing harrasing me. I have been a client of them more than 10 years but the service are getting standard as per name if not poor than standard bank.