I understand, When I was a new user I also used that option and it did give me the steempower after a week, so you may just have to wait little longer.

But I will say this again, you don't not need to wait 7 Days. Instead of selecting Power Up you can choose Buy Or Sell and you will enter the market, where you can sell for STEEM right away and then convert it to SteemPower, right away!