Hi there, Steve. I understand the importance of keeping your account details accurate and up to date.
When updating the phone number of your QuickBooks Cloud Services, I recommend contacting your hosting provider support team. They have the tools to access your account and change the necessary details.
To reach out to them, I suggest visiting this article: Hosting providers authorized by Intuit. Then, click your authorized hosting service provider. For visual reference, I've added a screenshot below.
If you want to update the information link to your QuickBooks Desktop account, you can access the Customer Account Management Portal (CAMPs) page.
Thanks for dropping by, Steve. Please know that the Community forum is always open to assist you again if you have other QuickBooks-related concerns.