Can’t restore the full game purchase. – Draw a Stickman: EPIC 2 Review

I purchased this game for my son for 1.99 and I have attempted to restore the purchase multiple times but it will not allow him to play the third level and wants me to unlock it again. I have the App Store receipt and don’t know who I can turn to in order to get it resolved.
Review by Mumbling Mac on Draw a Stickman: EPIC 2.