Why did i get changed twice for iTunes? (THIS HAPPENED TWICE)

ok so i check my bank account all the time. Last month well last time i got paid (every two weeks) i was charged by itunes for my Apple Music which is normal but it happened twice. I thought my mom took money out of my account first but it happened again just this Thursday. Can i get a refund i dont know why apple is taking my money. Also why are they taking 16 instead of 10