Extremely sad to hear what happened with you.

But can you or some one else please explain how exactly this happened?? Because from your post it is my understanding you were using two of the most secured wallets out there 'ledger nano' and 'electrum'
In ledger nano it asks you to confirm in your hardware if you want to send the transaction. In electrum there is 2FA which you will need to enter before sending anything.
So how exactly did this happen? Even if you plug your ledger nano to any other wallet, how exactly the seed go taken out??
Please explain so no one do the same mistakes again.