Sorry this is days late and you might have already reached out to the developer or asked for a refund, but I don't think this IF supports IOS devices.
If you haven't, you might reach out directly to the 13league's to confirm if this true. If it does not, you might try and play on another device it does support or seek a refund. But honestly, your device is probably only capable of playing the free online games anywhere but the apple app store, sadly. I hope that you will or have been able to resolve your issue and find games you can play.