What billing to choose for a web service?

Question

Billing systems

There is a web service for sale to legal entities. Only one service with several tariffs.
Tariffs in the format of a monthly fee with a prepaid number of "parrots". Subsequent parrots are charged separately.
We need simple billing with functionality:
- debiting funds from the client's account based on the tariff and accounting of parrots;
- depositing funds into the account;
- the possibility of recalculation at a different rate;
- unloading statistics on write-offs/charges;
- financial/administrative blocking of the service.
In my opinion, the functionality is quite simple, but I don’t want to fence bicycles. I don’t want to spend a lot of money either, because this is more of a reconnaissance in force than a real project.
Google offers a variety of billing options for internet and hosting providers. You can probably use them.
Please advise a solution.