Fun fact, if its the same FC, report them. Continuous invites from the same FC is considered harassment even if it's from different ppl. I had this conversation with a GM before.

Also FCs that send blind invites are the worst to join. If they cannot even bother to send you a msg and ask if you want to join, they don't care about you, they only want to pad their numbers. Blind invites in any game are the #1 indicator of poor guild leadership imo.