Great to see you here in the Community, @sarah17. Some of the QuickBooks Online Payments users have a limit of how much they can get paid online in a 30-day rolling period.
The number of online payments you've processed in the past 30 days can also affect the limit your customers to pay you online. Once you reach the processing limit, your customers won't be able to pay online until your limit opens up again.
Alternatively, they can still pay you through cash or checks.
You'll want to increase your limit by reaching out to our QuickBooks Payments support. They will ask you for some official documents to see how your business is going.
In case you have more questions about QuickBooks Payments, you can check our articles:
Let me know if you have any other questions. I'll be here to answer your next posts. Take care.