Mtn cancelation and refund please

HHi please assist, I ordered a router from mtn online, they said I do have a coverage in my area only to find out there is no coverage and the router couldn't connect. The courier company came to collect the router, and when I want to proceed with the cancelation Iam told to provide the IRMS NUMBER which I don't have. I have been telling them I don't have any irms number with me, I only have the shipment reference which was left by the courier guy from dsv.. my ID no. *** cell no. ***. I just want my refund because the router didn't work for me.