Concept of Economic Duress : One party can withhold payment due to other party and can release it only if other party signs "full discharge voucher".
Courts will grant relief in such cases. DICITEX FURNISHING LTD case. Supreme Court dtd.13/11/19 in CA No.8550/19
Source: https://www.linkedin.com/feed/update/urn:li:activity:6610072513546416128