Once a user is blocked on Qmarkets system he cannot access the system, his data is saved for your company internal analytical purposes.
If you wish to remove the users personal data (name, email, etc..) you have the option to anonymize users. Anonymizing a user allows you to keep all information regarding his ideas and input on the system but protect his privacy in aligned with the GDPR regulation. This is enabled after blocking a user.
For elaborated step by step introductions on how to anonymize please see the User Anonymization and Privacy article
https://help.qmarkets.net/a/solutions/articles/44002248601?lang=en&portalId=44000118545