Legal analysis: I became a guarantor without signature, which may be caused by someone else's fraudulent use of ID card. It belongs to contract fraud. The parties can communicate with creditors to prove that they have not provided debt guarantee, and then report it to the public security organ for handling.

Legal basis: Article 224 of the Criminal Law of People's Republic of China (PRC) commits one of the following acts, in the process of signing and performing a contract, defrauding the other party's property for the purpose of illegal possession. If the amount is relatively large, he shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention, and if the fine is huge or there are other serious circumstances, he shall be sentenced to fixed-term imprisonment of not less than three years but not more than 10 years, and the fine is especially huge or there are other especially serious circumstances. (2) Mortgaging with forged, altered or invalid bills or other false property rights certificates; (three) to perform a small contract or part of the contract first, to deceive the other party to continue to sign and perform the contract, and to have no actual performance ability; (4) After receiving the payment for goods, advance payment or secured property paid by the other party; (5) defrauding the other party's property by other means.