There was change in payment method. Previously added credit card got changed. Now, i have added bank account and mandate also completed, but details are still not update

Hi there, raman-h. 

I appreciate you for taking the time to post here in the Community. I want to make sure you're able to update your bank account information in QuickBooks Online. 

But before that, may I ask if you encounter any error messages? 

If none, it's possible that the changes made in updating your bank details were not reflected after saving it in QuickBooks. Also, ensure that the new bank account is not expired.

Aside from that, there are times when a browser's cache data becomes full of frequent access to web pages or damaged. To better isolate this issue, let's try signing in to QBO using a private or incognito window. This mode doesn't use the existing cache data and helps us confirm browser-related issues.

Here are the shortcut keys:

• Google Chrome: Ctrl + Shift + N 
• Mozilla Firefox: Ctrl + Shift + P
• Safari: Command + Shift + N

If you're able to see the updates, let's go back to your main browser, then clear its cache. This helps eliminate browsing history and start to refresh the program. Otherwise, try using other supported browsers.

For additional reference, please check these articles:  

• Update billing, payment, and subscription info in QuickBooks Online
• Update the payment method or info for your QuickBooks Online subscription 

If you need further help or assistance in updating your payment method. Just leave a comment below.