A guy from india got into my friends imessages gc

So i was chilling and i got a text from a new group with all my friends and a guy who had +91 in the start of they’re phone number so i was pretty freaked out but i did some research and found this website anyway he sent a blank text i said who the flip is this he i waited around 2 minutes then removed him and left myself and i did a bit more research and found out this guy was from india and there were five of us all using ios so i dont know where he came from or was it a glitch