No worries. Did it actually ping you properly? From a brief search on search-lemmy.com, it seems it’s up to each individual app/client to do a substring search for mentions of your username. For another user to “mention” you (make a clickable link, but not necessarily notify you since that’s not implemented apparently), they have to manually link it: @[email protected].
It’s very similar to Twitter, I’d say even more than Lemmy is to Reddit. Mastodon federated like Lemmy but in practice you can follow anyone from any instance. You just need to follow people using @username rather than just @username
I'd pick the person. (lemmy.world)
Twitter/X removing the block feature (lemm.ee)