Wifi Router cancellation - no help re cancellation or refund

WiFi Router suddenly has no coverage in KZN. I get told to return it to the store and my contract will be cancelled and I'll be refunded. I return it to the store and now I get told that I must contact the Call Centre to cancel etc. I have been on the phone for over 1/2 an hour and not one person I spoke to, knew what I was talking about. Surely the Store should follow up that someone call me and process the cancellation etc? They benefited from the initial sale after all. During all this time, debit orders are still being deducted.