Faulty MTN home router

MTN has to do better, i ordered the mtn home router on the 20th september and received it on the 28th september. the router never worked and when i called i was advised to take it to the nearest store which is Limpopo Mall MTN store. I took it there on the 4th of October and they confirmed that the router is indeed faulty and they are going to order for an exchange. weeks later, the router is still at the store because they're struggling to get the IRMS number and there is nothing they can do, I called MTN and I am told if the store doesn't have the IRMS number I should just wait. How do I go about this because I am paying for a service not rendered?????????MTN do better please