No reply or reaction to GDPR "Right to be forgotten" request. What now?

I've tried the contact form at the footer of an older & seemingly abandoned forum where I have an account, in order to make an informal request to remove my account & data and to also inform me about it.
The forum is very old and does not support any function for the user to delete their accounts or even comments made. The forum does have a cookie banner, although just one where the only option is to accept, so …

gdpr privacy request right to be forgotten