Good day

A supplier send a voucher to be used for our next purchase. I would like to know the accounting entry when we use the voucher.
We use Pastel


Purchase from supplier:
DR Expense R1000
DR VAT R150
CR Supplier R1150

The voucher is worth R500 off our next purchase

Payment of the supplier
DR Supplier R1150
CR Bank R650
CR Other Income?? R500


I would like to know if the other income entry is correct, or how should I process this voucher.
Thank you.

Kind regards,
Seun