My gmail account stolen

Hello,
Can you help please,
We are have been having the same issue for months,
The reply is that the email is unrecoverable, we cannot find any Gmail service to fix it and I had to create a temporary address to contact anyone,
although for months I have been getting spammed by my own Gmail address,
How do I get my Gmail address back that someone else is using and Gmail says is not recoverable?

Thank you and regards