This would not be possible through any automated method if you have lost the ability to prove that it is your Firefox Account.

There probably is a human somewhere that can tell you definitively whether it is possible and, if it is, how it will be done. Unfortunately, I haven't been able to uncover the correct contact method so far. (It isn't through this support forum, though.)

@jscher2000 it's not like that. I have my email account, i have my firefox user name and password as well. This means i am the owner of the account. But unfortunately due to MFA and lost my phone i am unable to make second authentication.

The one worst thing with Firefox is that except forum we don't have support contact and hence no one is responsible. This leads user like us to seriously think and move toward Chrome.

Are you based in the EU? GDPR only applies if you live in the EU.

Otherwise, what data exactly do you wish to delete? Only your Firefox Account? How do I delete my account data?

@Tyler Downer, I am unable to delete my account or data. As once after login all screens asks for "Open your authentication app and enter the security code it provides. " which i don't have an access.

Now i am unable to create new account as well because Firefox says you email address already registered. Hence if someone from Firefox can delete my email address then i can start it from beginning and create new Firefox account.

I hope you understand the problem now.