Disgusting service and charges

I entered into a month to month data contract for home internet 3yrs ago. The setup was easy and now I'm struggling for 2 months to cancel it because the N1city store does not want to accept the router without the box. I'm going into the 2nd month of trying as they want to charge me R2500 for the lost box where the actual router costed R1500! It's insane how they charge an almost double penalty for a box!