That is a very good question. The best way to resolve your issue is to contact Apple because this is whom you have purchased the Slingplayer application from and they will be able to better assist you with this. The best contact number for Apple Support is 1-800-275-2273.
I hope this helps you!
Have a great day!
The Sling Media Moderation Team
Don't even bother with Apple their app return period is 15 minutes, and I doubt they will credit you any money back. Last when I called they pretty much told me tough luck when an app I recently purchased went on sale an hour later. What you will have to do is bite the bullet and buy the iPhone app because the iPad app doesn't work on the iPhone due to the resolutions of the screens.