The timing sequence is difficult to tell from what you have written but, if you received an email that your application had been received at the Home Office, you would be unable to cancel at that point.
Your online account should tell you the status (where it is in the process). If you are able to withdraw the application, it could be 2-4 business days, depending on when you submitted your request.
You should not reapply until you know the status of the current application; if you try to, the online system sees that you already have an account and an active application.
Cancel your visa, immigration or citizenship application
You can ask to cancel (withdraw) an application for a visa, visa extension or citizenship.
How you cancel an application depends on where you applied.
You applied outside the UK
Contact UKVI to find out how to cancel your application.
You can only get your fee refunded if your application hasn’t been processed yet.
You applied in the UK
You need to cancel your application using the online form.
You won’t get your fee refunded if you cancel an application that you made in the UK.
It’s sometimes possible to get your passport or other documents returned without withdrawing your application - you’ll be told whether you can do this when you fill in the form.
You may lose your permission to stay in the UK if you cancel your application.
You can’t stop the cancellation once it’s been received by the Home Office.