A man surnamed Zhang, of Weifang, Shandong province, feels duped by his ex-girlfriend Sun who refuses to repay him 20,000 yuan because she signed the IOU with her nickname.

Earlier last year, Sun said she needed the money to help her sick mother, and volunteered to write an IOU.

Late last year, Sun parted with him and refused to repay the money because the signer was not her, she argued.

A lawyer told Zhang to ask the police to verify that the IOU was signed with Sun`s signature, which could help him get back the money.