People calling baby Alex!

Ashley
I'm usually pretty thick skinned, but this situation has my blood boiling.
When my first son was born, we named him Spencer and told everyone right away. My grandmother refused to acknowledge that was his name, and called him Alex the first time she met him. I heard later through the grapevine (my brother mostly) that the whole family hated Spence's name. Usually I'd tell them to stick it, but your hormones are kind of out of whack a day after giving birth, and it really hurt me...to the point that I changed Spence's name to William for a day. Luckily, my husband helped me come to my senses, and we changed it back before anyone knew!
I spoke with my mom several months later about how angry and upset I was about the whole situation. My family are not the easiest people to talk to - they're "emotion ignorers" lol...  But I thought the situation was fixed.
This time around, we have decided to only share names we're "considering" in advance (read: fake names, lol). My grandmother has already started calling the baby Alex, and the hormones make me want to hit something. I never directly addressed the situation with her last time (I know, my bad), but I feel like confronting her now is not the best idea. 
I know there's no real solution other than to ask them to stop...but I don't wanna lol...this was more of a rant than a "please help" I guess, and I feel better for getting it off my chest. Thanks for listening!