Help with recovering emails

I’d check Mail > Mailboxes > Trash first, and also Archive/All Mail in case the messages were archived rather than deleted.

If this is iCloud Mail, Apple keeps deleted messages in Trash for up to 30 days. After that, they’re permanently deleted, so messages deleted a few months ago normally can’t be recovered from iCloud Mail.

If you use Gmail, Outlook, Yahoo, or another provider, recovery depends on that provider. I’d also sign in to the provider’s website and check there.

Which email service are you using? That would help narrow down whether there’s another recovery option.

Delete and recover emails in Mail on iPad - Apple Support

I’m sorry — given what the emails relate to, I can understand why you’re trying every possibility.

One thing I wouldn’t do is erase or restore the iPad hoping an old iCloud backup will bring the mail back. Apple says Mail data itself isn’t included in iCloud Backup.

Before giving up, search the email provider’s website directly, including All Mail/Archive, Sent, Trash, and search by the parking company’s name, email address, or words from the subject. Also check any other computer or device where you may have used that email account, plus Files for any PDFs or attachments you might have saved.

If you tell us whether the account is iCloud, Gmail, Outlook, Yahoo, or something else, there may be a provider-specific option worth checking.