Cash crusaders mall of Tembisa refusing to pay earned incentives

My husband's a top performer at mall of Tembisa hitting targets ,but incentives get docked due to late coming without prior written warning is this fair? Labour Law (BCEA sec 34) says deductions need written agreement. Can they do this?

.is late coming a valid reason to withhold earned incentives ? .was there a clear policy communicated to staff? .can we get details of deductions? .is this standard practice for all employees? .can we see the payslip stating that incentives were forfeited because of late coming

Thank you