Important Update: 

Delta cash is discontinued on 10th Nov 2025. For users who previously held Delta Cash in their wallet, that amount was automatically converted into Fee Vouchers on November 10th. This action simplified the reward system and established a clearer value for the reward. The conversion formula used for this process was: 

Fee Voucher = Delta Cash ÷ 15

For more info check this article:
Decode Fee Voucher