Even if they don’t have your comments, if you find a gdpr complaint they will have to show that. You can ask to see any data they have on you and also ask them to delete it. (If you’re actually going to sue them don’t ask them to delete it, though. You’ll need that in court.)
That sounds like a gdpr violation. Companies can keep some things under the gdpr even when asked to delete them but i doubt your comments or whatever fall into that category.