Monthly charges for unreturned equipment

Thanks for your response. So am I correct in my understanding that these monthly charges were not to cover the cost of the equipment, but rather non-refundable penalties for not yet returning it?? It seems like usually the non-returning charge is a one time thing for the cost of the missing router, which may be refunded once it is returned. But in my case I was paying what amounted to hundreds of dollars extra on my bills that had nothing to do with covering the cost of the equipment but rather a penalty? 

Or I guess I see in your response that it’s technically a rental. Ok, thanks for your time. It doesn’t seem like there’s anything I can do at this point to recoup all those charges that basically went down the drain, but figured I’d try just in case.