p.s. The scammer is using many different accounts on many different servers, and they are using unusual characters for their names (for example swapping capital i for small L) to try to mess up reporting.

The most effective way to stop them is to click ⋯ and "report" on *every* spam you see, and keep doing it until they stop appearing. If your interface includes the option to forward the report anonymously, select this option so that it goes to the server where the scammer's account is.