A forum-maintained blacklist is rejected by the operator for legal and maintenance reasons; the responsibility for a constantly current list could hardly be borne. Instead it is recommended to use the eBay rating system, possibly enquire in eBay forums and always buy carefully. Concretely topfitab40 (Stefan Zeilinger from Nuremberg) counts as a reputable supplier specialised in purchase and sale of used writing instruments, offers his own repairs, publishes real name with address and phone number and accepts complaints without exception. Several collectors confirm positive transactions including originality confirmed by the maker.