RSVP yes but i have no idea who they are ***UPDATED MYSTERY SOLVED***

ok so today we receive a bunch of RSVP's back, now what i did was put mine and fh's name on the RSVP envelope but put his address on rsvp envelope. Today he called me to tell me who rsvp'd. Well as he is opening them and telling me each person with their answer, one of the rsvps we get back i was like 'HUH who is that?' fh is like i think its your side, i tell him i dont know anybody by that name and dont have it on my guestlist. I double checked my guest list and nope they are not on it, i even double checked the excel sheet i sent over to wendy for addresses and nope they are not on it. I call my dad and he doesn't know who they are. Fh said he'll ask his mom maybe its somebody from work. She gets home and she doesn't know who they are either. Now we are all confused, but they rsvp'd yes ...and whoever it is did respond quickly. But i dont understand. I mean maybe it was sent to a wrong address but who the h*ll would respond yes if it was a wrong address

THIS IS INSANE
****UPDATED******

ok my dad is going to drive me insane. Can i tell you that from december then january i sat down with my dad to help me with the guestlist and from our side who to invite, family and friends and he made a list. I asked dozens of times after and no didnt need to add anyone. AFTER i started sending out he realized were missing like 20 ppl, luckily i made a bunch of extra invites. Some he took from my apartment and said he is giving them to ppl in person, i told him to let me know ASAP who he gives it to. ANYWAYS yeah i called my dad to ask who this person is and he said he doesn't know. My mom just came home and she knew right away lol, its somebody my parents know for 20 years or so lol. Once my mom told me i remember him from when i was younger i just dont go to alot of functions for a while now and didnt know his last name and wasnt informed he was given an invite, my mom told me my dad gave it to him on monday. I just called my dad and told him and hes like 'YEAH TONY i invited him' i said i told you his name before, but oh i said antonio instead which is what was on the invite so my dad couldn't put 2 and 2 together but he doesnt pay attention half the time