Worst Service ever

I took a month-to-month contract for a home wifi router and I was not happy with the service and have been trying to cancel the contract since the 15th of September but I have been sent from pillar to post and am still not able to cancel. I was told to take the router to the store to be inspected, and once I receive the reference number to call and finalize the cancellation online. I took the device to the store but online everyone was not assisting, The cancellation department pointed me to sales, and sales pointed me to cancellations. The Manager is nowhere to be found.