Hi, you should have changed email addresses prior to it being stopped as there is a no way to do that now. Since can not answer from the deleted account, you are now locked out as no way to prove you are you.

Make a new account using your 2nd address. Note : that Sync is for Syncing Devices and is not a backup service and you will eventually loose your data if you use it as such. Just like now.

Please let us know if this solved your issue or if need further assistance.

Can't you use that second account to login to Sync and make it the new primary account?

• https://support.mozilla.org/en-US/kb/change-primary-email-address-firefox-accounts