This happened to me one year. My dad bought himself the book I was getting him so I gave it to my uncle instead who liked the same author

Simple, return it?

Revenge Plot 1. Return it 2. Get money back 3. Find out what he got you 4. Use the money you just got back to buy the same thing he got you 5. Come home holding it in your hands, happily saying you decided to surprise yourself

This is exactly why both my brother and my dad are *forbidden* to buy themselves anything after mid-November. They have a habit of buying exactly what someone else bought them as a Christmas gift.

I can understand the FML point, but it's still a kind gesture. If it's worth giving, he'll appreciate it. Besides, he has spares. Can't go wrong with spares for any sort of crafting, Calligraphy included.

give it to him as a backup.

If your family gives Christmas presents to reach other, buying things for yourself right before Christmas is a really bad idea for exactly this reason. Sorry your present got ruined, OP.

If your dad loves you, he'll accept it anyway. And if he loves calligraphy that much, a second kit won't be a bad thing.