Photo contest on facebook

Some pretty big magazine did a photo contest on facebook in June. First they said there was one winner. A client asked me to participate with a photo I took. I said fine, I mean I'm happy if her animal is on a cover.It didn't win. Suddenly now in february, my photo is on a cover. I didn't know anything about it, nor did I get asked. After asking my client, she said she gave the magazine my contact and told them to ask me too. But they didn't. And didn't even give me credit.Now I've learnt that they've expanded the contest later to 10 more winners. Then the next few winners and so on and so on. So they're still using images from that contest in June for covers until now.And no, in the first post where they gave information about the contest, they didn't say that it will go on that long.Is that even legal? via /r/photography https://ift.tt/ZYmsJHz