Still asking me to buy even though I already bought the app – Infinite Painter Review

I really liked the app so I decide to purchase it before my free trial ended. However, once the trail ended the app locked its multiple function and asking me purchase it again, now I can not use the app properly, and seems like I can’t get a hold of the customer service. If there is a support team and you happen to see my review please contact me I have the receipt from the App Store.
Review by Moxflare on Infinite Painter.