Request refund for Sky Safari 6 Pro for Android and apply payment for Sky Safari 7 Pro for IOS.

I purchased Sky Safari 6 Pro for Android and have been unable to complete the installation and download.  File download failed repeatedly.  This is a known issue and nothing in the knowledge Base helped.  I have uninstalled SS6Pro from the Android and am purchasing an iPad.  I want to apply the refund to purchase of Sky Safari 7 Pro for IOS.