Family calling your kid by a name you hate

Anyonr else have this happen? I just need to vent here for a second. My 2 years old sons name is Jasper, and we picked that name for him because we love how it sounds and we feel like its fitting for him and for our tastes. Well my husbands uncle has suddenly decided that he is going to call him Jazzy. He decided this without asking if we were cool with it, and when I asked him not to call him that, he just said that he was going to and reminded my mother in law of how he did the same thing to her oldest son. I dont like how it sounds, I knew someone named Jazzy as a teen and hated her, it isn't fitting for a boy in my opinion, and its not his name. He is almost 2, and he has always been Jasper to us, and has always been called by his name by everyone until today.... I'm really not okay with it at all, and my husbands uncle doesn't give a shit that I just want him to be called by the name we gave him. If he was a teen or an adult and decided he wanted a nickname, thats fine. But he is a toddler, so we are the ones that dictate what's he's called until then. We gave him his name, and I love his name. Okay, rant over...

Sincerely, JASPER Henry's mother...