Small update of my case. Stake asks me to verify my account at level 4 to access it to unlock my account following a suspicion of multiple accounts.

I had no KYC, I hardly passed the 3 levels. Many documents requested.

For level 4 they ask me for a payslip. Being self-employed, I declare my turnover quarterly.
I sent them a quarterly statement of turnover, the only document to prove my professional income.

They refuse the document. They don't understand that I'm not an employee.