Payment subscription

Hi , I have an overdue payment for an application that was on free trial and now renewed on its own for an annual charge, I never used the application and will not use it that’s why I don’t want to pay the annual fee while not using it. My apple id is now blocked from downloading any application due to payment and if I placed my card again on my id a charge will be taken for the unused app.

what can I do without paying the amount ???