PAYG without top-ups, does it exist?

So I was thinking yesterday (potentially dangerous) about the ongoing situation with my parents and their $8million dollars in phone credit they never use.

(To catch anyone up, they’re both on PAYG, rarely use their phones but still have to put in a $10 phone card every month, Dad is sitting somewhere over $100 in credit that if he misses the expiry date, whoosh there it all goes)

Anyway, then it came to me, my moment of brilliance. Can anyone tell me if this exists?

You have a phone, you buy it, however much, and it’s PAYG, but instead of having to top it up, it’s linked to your credit card. So everytime you make a call, it just charges you. .50cents a minute, $1 a minute, whatever.

It probably does exist out there somewhere, like every great invention i’m always a step behind, but if it doesn’t…don’t any of you dare steal it! 🙂

(Or if you can make it happen, I’m happy to sell the idea off 😉