My authenticator got lost and I wasn't able to open all of my MEGA Accounts, so what I did is I contacted their support team and told them my problem, they was able to resolve my problem in less than 2 days and I was able to retrieve my accounts back, without 2FA and losing my contents. Just be honest with your concern and they will take action to it immediately after you got a ticket. I was on MEGA for like 3 to 4 years now, so I know that I enjoy their services and support. Thank you and have a good day!