Harassing me over their own fault

I had a Vox account that ended almost a year ago in February 2017. They contacted me to retrieve their router and I supp**** them with the landlords details of the house since I moved out. Now almost an entire year later they are charging me for the non collected router. How the hell must I help you now a year later, they were supposed to fetch it a year ago and never did and now they want to blame me. I am not responsible for YOUR collection not happening, YOUR company did not fetch the router and now a year later its just bad bad business. So stop harassing me and stop taking money from my account as you are *****ing from me, I gave no permission for you to use my account details one year after cancelling my contract with you!!!!!!