(offtopic from Mobile phone repair shops, but relevant to the wiki in general)
Yes, they have been and continue to be a problem. Their OSM account has just emerged from a relatively long OSM editing block. See also previous OSM blocks.
If you think that their activity on the wiki is bad enough to warrant a block, please message one or more wiki admins to request it. I’m on that list, but as I’m not one of the main wiki editors I don’t think that it would be fair for me to act unilaterally (but am more than happy to provide evidence and support). For more about this user’s intent and activity, see their user page and talk page.
I believe that Ti-Lo/RTFM’s contribution to the project as a whole has been profoundly negative.