unauthorsied fees

I joined the planet fitness a 2 montsh ago , upon taking the package i was not told that in December planet fitness take 2X PAYMENTS which i think is unfair seeing that i just joined not even two months ago and took a 3 month contract ONLY.now why do i have to pay planet fitness staffs bonus with out knowledge , you are ripping people off , who pays twice for things, that i want my contract cancelled at no cost i have already joined another gym