Making sure that you have the correct data in your QuickBooks Online (QBO) account is important so everything will run smoothly, @Maj S. Worry not, because I'm here to give some details on how to resolve the wrong account number entered.
To begin, may I know the specific article you've followed? I'd appreciate it if you could add this info so I can double-check and send feedback to our content team to make the necessary edit. Alternatively, you can mark the article in question as unhelpful by clicking the No button located at the bottom of the page. Please see the screenshot for reference:

Then, you can also schedule a callback request to save a spot on the queue and be called as soon as the phone support line is open. Here's how:
- In your QBO account, click the Help menu.
- Then, select the Search tab and choose Contact us.
- Next, type a brief description of your concern and select Continue.
- From there, choose the Have us call you button.

The program also has a compilation of self-help videos that you can access to have a guide in doing your QuickBooks tasks. Browse through this page to get started: Learn about QuickBooks Online with how-to videos.
Please post again here in the Community if you have any other concerns managing your account. I'm always here ready to provide further assistance to ensure your goals are met. Have a great day ahead.