How can I change the phone number on my account cos I lost the phone with the phone number ?

Let's work on this together in changing the phone number attached to your account, David. 

All we need to do is to log in to your Intuit account. This way, we can update the information, such as your security, profile, preferences, and more. We can also change our phone number here. 

Here's how: 

1. Login to your QBO account. 
2. Beside the Gear icon, click the Name logo.
3. Select Manage your Intuit Account. 
4. On the page, choose the Sign in & Security option. 
5. Hit Change, then add the phone number. 
6. Click Save. 

The screenshot is attached for visual reference. 

Doing this will allow you to verify your moving forward transactions in your Intuit Account.

Furthermore, you can refer to this article to learn how to change your business information in QBO: Change your business name, contact info, or EIN in QuickBooks Online.

Feel free to reply to the thread if you need additional assistance managing your credentials in QBO. I'll keep an eye out for it. Take care.