Bonus airtime not received

I bought airtime for R80 on 23/11/2021. As per my price plan i should get R80 bonus airtime which i realised at 21:19 pm when i want to make a call that i did not receive it. Vodacom is refusing to credit my account when they clearly failed to fulfill their promises. Why is it my problem that i must police them to check if their system is doing what it supposed to. They are failing to take the responsibility for the system issue which is clearly not my fault at all.