Your Parcelforce manifest can only be accessed directly through your Parcelforce account. You are usually only charged for a shipment once Parcelforce scan the label (always check with your Parcelforce , so should you need to cancel any labels, just discard them.
If you're unsure of where to manifest I recommend you contact your account manager and they'll be able to show you exactly where to find this page within your account.
If you have any queries about this, feel free to contact support and we'd be happy to help.