MTN HOME WIFI IS TRASH!!!

I bought a home Wi-Fi in March and the data runs out within 5 days. I want to return it, and they are telling me they won't take it unless I bring the whole box back. I told them I lost the box and I'm willing to pay for it, but they still don't want to take it back. so, I am basically paying 269 every month foe something I'm not using