A person lent a substantial sum and received a blank cheque as security. When the cheque was presented with accrued interest, it was returned marked 'unusable'. The bank revealed the issuer had previously instructed stop payment on multiple cheques, claiming they were lost. Despite a legal notice, the issuer has retaliated with false allegations of a joint finance business and coercion. The lender seeks advice on how to prove the issuer's intentional deception in court and proceed with a cheque bounce case.