Is it Islamically permissible to waive financial dues in exchange for a sponsorship transfer under duress, and is the sponsor Islamically absolved by this waiver? Is it permissible for a worker to work for his own personal benefit during part of official working hours and have the earnings deducted from his dues?

The contract concluded between the worker and the employer is the arbiter between them. If the contract stipulates entitlements for the worker at the end of service or a specific period, the employer has no right to compel him to waive them. If he waives them under duress, he has the right to claim them later. However, if the agreed-upon period in the contract ends, the employer has the right not to be bound by post-service benefits. The worker may claim his rights through available means if he is unable to obtain them, provided that he does not wrong the employer.