I'll share insight on how you can proceed with this query on QuickBooks Online (QBO).
If your payroll subscription plan's charge is £1 per paid employee, the option to cancel this type of payroll is unavailable. If you no longer use the service, then you won't get billed for it.
Otherwise, follow these steps:
Also, ensure you ran your final payroll so that HMRC will be notified. I'll leave these articles for your reference:
Tag me in the comments below if you need further assistance. I'll get back to you as soon as I can.