No you were blocked most likely because content in your repo was flagged for a reason maybe copyright or data that shouldnt have been there. It is possible the algorithm made a mistake though. People were blocked before for uploading stuff that didnt belong to them to distribute to others.
As I said, since you are a free user, you will have to wait for Gitlab to deal with your ticket as paying customers are a priority.
If you cannot wait for support, then perhaps you should have considered a paid account? You mention about using Gitlab for professional works, and you being impatient when expecting someone to unblock your “free” account immediately. If your work was so important, perhaps you should have been paying for support to guarantee being given assistance when things go wrong?
Alternatively, you can run your own Gitlab server and be the administrator of it. And then if something bad happens, eg: you lock your account or forget your 2FA/lose the device, you have the ability to unlock/unblock any time you want since you can do it yourself.