Very slow download

I rented a movie with my iPhone and is taking a lot of time to download.

After 2 days downloading only 20% is downloaded. I also clicked to view the rental and now it says that i have 20 hours left to see the movie. But the download timer says that it will take much longer to download.

I am connected to a wifi network with a very fast connection to internet.

Can you help me?

I also rented another movie with my appletv and is taking several days to download also an is not done yet.