The reason you can't update credit card information for a QuickBooks Desktop (QBDT) subscription via the Help menu is that billing is managed securely through the Customer Account Maintenance Portal (CAMPs), not the general help section.
Here are the steps in signing in to CAMPs and updating your credit card payment method:
- Go to camps.intuit.com.
- Sign in with your Intuit Account user ID and password.
- If you see multiple accounts upon signing in, select the one you want to open.
From the Payment Method section, find the card or account you want to update. Click Edit, then enter your updated payment information. Once done, select Save and Close.
It's great that you didn't provide your credit card information to the customer service representative you spoke with. Your caution is completely justified, and it's best practice to update your payment method securely through CAMPs.
Don't hesitate to post again here in the Community or leave a comment in this thread if you have any follow-up questions.