All is not lost! Do not worry!
First of all, I agree, the old forums were much easier to find as you could “report” a word directly from the course and go straight into the forum. Now you have to navigate your way here in a more roundabout way …
But to answer your main question: it is entirely possible that the original course creator you mention, “jestersuave”, is no longer an active member of memrise, but in order to find out whether this is the case, two things are necessary.
First of all, could you post a link - or links, if there are several courses - to the courses you are interested in?
Secondly, if you wish to improve the quality of these courses, that would be fantastic! In order to find out if you can do that, @Lien needs to contact the original course creator to find out if you could be made a course contributor for this course. You would then be able to access the database(s) for the course(s) and make changes yourself.
Would you be interested in being able to do that?