Will a Nexus 6 purchased from AT&T work on VZW? topic

I purchased this on eBay, and the description said "carrier unlocked", but when I popped in my VZW SIM, it gives me a message "SIM network unlock PIN" I just pressed dismiss through this, thought everything was working because I'm connected through wifi. I can send and receive SMS, and make voice calls. When WiFi is off, I have no data connection. Am I screwed, or is there a way to unlock this from AT&T?