Loan security cheques are illegal

Despite instructions from Qatar Central Bank, the Banks are demanding cheques (undated and post dated) as security from the customers against the credit card and personal loans. The banks are into a contractual business where they do civil transactions, how then they are allowed to obtain cheques and make their civil transactions into criminal transactions, because on cheques criminal case with the police can be registered, whereas civil transaction disputes are settled through the civil courts. Perhaps the banks have not clearly understood the QCB instructions, that needs re-clarification.