Cheating with Home Loan Customers

I am struggling with Standard Chartered Bank to close my home loan account. I have made payment of full loan amount >6 weeks back on 29th of February as per bank requirement (PTQ). Still as on date my loan account is not closed, rather bank has debited arbitrary amount to my account without any explanation, despite of number of request reminders neither they are giving any justification / calculation of amount debited to my account nor closing my Home Loan Account. Very clearly SCB want me to pay illegitimate amount to close my bank account, they are saying if I ready to stay they can manage that amount? this is a type of extortion. I am strongly recommend not to use a multinational bank involved in unethical, illegal, arm-twisting practices.