Let me share some information your QuickBooks Online subscription.
Once you're account has been cancelled, you will be prompted to resubscribe as soon as you sign into the QuickBooks Online company. If not, you may follow these below:
Sign in to your QuickBooks Online company.
Click on the Gear⚙ icon at the top.
Under Your Company, choose Account and Settings.
Select Billing & Subscription, then Resubscribe,and enter the updated billing information.
Click on Subscribe.
Next, to prevent back-billed charges from occurring, check the next charge date.
Here's how:
Log out, then log in again.
Go to the Gear⚙ icon, then Account and Settings.
Select Billing & Subscription.
If it's a date in the past, I recommend contacting our Support Team. They have the right tools to help you review the account and make sure your billing date is up-to-date.
I've also added this articles that you can use as a reference: