When you buy an app on the App Store, you provide your payment details to Apple, which ultimately processes the transaction and offers the app stored on their servers. I don’t have access to your payment details nor to your email or contact information, so I cannot offer a refund. But Apple can.

Unfortunately I don’t have any control over the app download/update process. The App Store is operated by Apple and the downloaded/updated apps are stored on Apple servers. Apple has an official help article for these issues: https://support.apple.com/en-us/102331 If you end up contacting the Apple Support, they’ll most likely tell you to contact the third-party app…