Wrong Handset

I was approved for a contract on the 13th February for the handset i wanted. 3 Weeks went by with me calling back and forth for answers only to be told that they have no stock and cant say when they will be getting in. I asked that they cancel which they did and i app**** for another handset. This time i was provisionally approved with a limit which i was not happy with but agreed none the less , I needed a new phone because mine is on the blink. I specifically asked the lady what size storage , she rep**** 128gb. What colour , green and grey , I asked for green. Today they deliver a handset , gray in colour and only 64gb storage. Do I cancel again , can they swop this and send me what i asked for and what was promised in their recorded calls they have for their reference?! Email MTN they refer you to Mondo , call Mondo the system is always offline. No use in emailing or chatting on the messenger app for FB because you chat to an autobot with the most limited menu ever. Can I please have feedback as to whether this phone can be returned and i can be given what i ordered? I am even willing to go to a store myself to swop if need be.