I'm a Little lost

I got a Straight Talk Samsung Galaxy J7 for Christmas. Went to activate it. Waited. The device says the serial number is invalid. Called customer service a couple of times. The last time was a port issue of the previous number that tech support was working on. The call ended suddenly as all the data that the phone came with was used. The ticket history says those tickets are closed. I don't know if they fixed it or not. I have no phone now as my previous one was deactivated in the port process. I have no data to call them again.