My fiancé and I are having a small wedding (40ish people) on May 4th, 2017. Only close friends and family are invited. My MIL wanted to invited 6 "close family friends" and was told no multiple times. We explained if each parent invited 6 friends we'd have 24 additional people. In the end we decided to let her bring her best friend as a date since she is single and not very comfortable around her ex and his new wife. Now we are less then 2 months away and she tells us her friends, a couple (husband and wife), already booked all their stuff so they are coming! They received no invitation/save the date/were not invited to the shower! They have not even had any contact with my fiancé and I. It's so rude and I'm unsure if I should just let them come since they can't get a refund now or stand my ground.
(Especially since my parents, who are paying, even listened when told no friends)