Congratulations Apple User Pop up won't go away

Ok, in the last 12 hours, I've posted this same issue on here three times (counting this one). I cannot find the question ANYWHERE. So here it goes again.

On my iPad with current IOS, every single time I click an article on Yahoo, I am presented with a pop up saying something like "Congratulations apple user, you've been chosen to win a $1000 Amazon gift card,"... and some other prizes if I answer some questions. This is obviously a scam. There is a "close" button, but any action I take redirects me to a site "free-award.com". I have tried everything I can find to stop this. I've deleted my history. Restarted my iPad. Tried to find help from the yahoo communities, but they're as helpful as Yahoo customer support. So last night I posted this question here. When I tried to follow up, I couldn't find the post. So I did it again. This morning, tried to follow up. Couldn't find the post, so I'm posting again (#3). So really this is a double question. How do I rid myself of this instrusion, and why do my posts keep disappearing?