Go to (while logged in, if allowed) or check the suspension email for a data export link.
If none of the above methods work, you can try contacting Google Support: how to unblock a gmail account
If your account was blocked due to suspicious activity, Google might ask you to review your account's activity. Check your account's recent activity, such as login history and sent emails, to make sure there's no unauthorized access. Go to (while logged in, if allowed) or