Thanks for reaching out here in the Community for support. I'd be glad to help out and show you the steps to reactivate your account and reach assistance by phone as well.
Your QuickBooks Online account may be showing canceled (or on hold) if your debit or credit card on file needs to be updated. This can be after logging in, then:
1. Click on the company showing as canceled.
2. Choose the Gear icon in the top right corner.
3. Select Account and Settings, then the Billing & Subscription tab.