Back when we were still flying, there was some outfit pretending to be a UA rebooking office that was charging hundreds of dollars to simply cancel tickets (and not attempt to get refunds or vouchers to which the passenger was entitled). The name and website looked official, and of course was vague about their service fees for the non service. At one point, links and the phone number were briefly posted on FT. I always suspected that these scammers operated a version for each major airline.