To use your opay cashback to buy airtime:
1: you will need to sign in to your opay account by filling in your mobile number and password.
2: In your account click on Airtime, when you enter, select or fill in the amount of airtime you want to purchase and proceed to checkout.
3: now at your payment checkout page look closely and you will see a switch button where it is titled... (use cashback).
Click on the button and you will see it turning on.
If your cashback is up to the usable amount then it will allow you to use it for airtime purchase, if maybe your airtime amount is not upto the usable amount it will join together with your main balance and give you a discount.
Example:
Cashback is 100 naira and there are more money in your main balance.
If you were to buy airtime of 200 naira and you turn on both cashback wallet which is 100 and main account wallet.
Instead of the app to charge complete 200 naira from your main account wallet, it will charge only 100 naira and the rest 100 naira will be taken from your cashback account.
How to withdraw opay cashback to bank:
According to opay platform, the cashback is not withdrawable. You can only use your cashback to purchase airtime and data.
Read this to be safe from opay scam: Is Opay legit or scam?