Mtn ***** service provider

I purchased a rooter at the mtn store at campus square when I opened a month to month home wifi contract with them. The guy advised that a rooter needs to be bought upfront which i can keep. Now a year after I've canceled the contract they want to black list me for a months premium and tell me that I need to bring the rooter back in order for the cancelation to be finalized after they said I can keep the rooter which I paid for.. How does that work this is very ***** really!!