Welcome to the Community, @pennywise77.

If you have active clients in your QuickBooks account, you can use QuickBooks for Accountants for free. QBOA won't charge you anything even if you provide them with your credit or debit card details when subscribing to the service. The information will only serve for billings and subscription.

You can also contact our customer support team to check your accounts to see if the clients' information is attached correctly to the QBOA firm. To do so, here's how: 

1. Sign in with your QuickBooks Online company.
2. In the upper right corner, click on the Help icon.
3. Select Search, then click Contact Us.
4. Write your issue or concern and Continue.
5. Select what support you would like to contact.

If you want to manage your users in QuickBooks Online, you can visit this article for more information: Add and manage users in QuickBooks Online.

Feel free to contact us if you have other questions about why QBOA needs your card details. The Community space is always here to assist you.