Went through the site Cryptorefill..
100k is just for a single unit I.e if you redeem it on Jumia you will get 100k to use on your order.
On the checkout page , you will see something like this beside the order details :
@74.07 per USDC..Change the quantity to whatever you want, by default it selected 5, not sure if that’s how it should but you can select up to 10.. This implies that you will get 10 Jumia cards that can be redeemed in order as vouchers , not sure how the redeem aspect works but you should figure it out.