Cellphone purchased but defective

on 23/10/2017 I purchased a hurricane groove dual sim, upon returning to my offices I put in the sim cards but saw that it was reading the sim cards, I noticed that its not reading them, it just said emergency calls only. I called the store on 24/10/2017 and I enquired if I can swop the phone for something else or get a refund but they refused. someone needs to help me because the phone is constantly going to emergency calls only and because of this I can make or receive calls. MTN is the service provider for this mobile and they should live up to the level of standard that they give all their customers. I find the fact that I cant get to swop or refund for this defective item abhorrent.