A friend borrowed 20 thousand and didn't pay it back. He wrote on the IOU that the guarantor was me, and his signature and fingerprints were there.

Guarantee law

Thirtieth any of the following circumstances, the guarantor shall not bear civil liability:

(a) the parties to the main contract collude to defraud the guarantor to provide a guarantee;

(two) the creditor of the main contract uses fraud, coercion and other means to make the guarantor provide a guarantee against the true meaning.