debited with no decoder

My decoder broke in April so I cancelled my subscription I tried again in may and still no luck so I cancelled it.... This month out of the blue I got debited for monthly installments which is odd since my decoder is not plugged or working, when I called the call centre the unhelpful agent said it was don't via self service which was never done by me, how is this possible since I never fixed the decoder or resubscribed? I should be reimbursed since this is totally unfair