This issue is not related to Punchh functionality, but the Apple Store itself. From Apple's documentation, please see the following. If issues persist, please reach out to Apple Support for assistance.
Top Tips to Fix Can't Download/Update Apps in iOS 12/11
Fix 1: Sign out and Sign into the App Store
The first thing you need to do is make sure the Apple ID for App Store is right or not. If the Apple ID has no problem, try to sign out and sign in to App Store to settle the issue.
Go to "Settings" > tap "iTunes & App Store" > tap the Apple ID > tap "Sign Out" in the pop-up > tap the Apple ID again and sign in with your Apple ID.
Now, run App Store to download apps to check the problem is solved or not. If you find "cannot connect to App Store" on your device screen when you are download and install apps, fix it first.
Fix 2: Check the Wi-Fi Connection
If you're using cellular data or Wi-Fi and have issues with app downloading, try to connect to another Wi-Fi network. To check the Wi-Fi connection, try watching a video from the Internet. Get help if the Wi-Fi is not working.
Fix 3: Delete and Restart the App Download
If the app fails to download or update, you can try deleting the app and reinstall directly.
Fix 4: Disable Restrictions for Installing Apps
The iOS Restrictions disables certain features of the iPhone, including the ability to download apps. So, if you can't install an update, the function may be blocked.
Go to "Settings" > tap "General" > tap "Restrictions" > enter your passcode > check "Installing Apps" and turn on the updating feature.
Fix 5. Check Available Storage
If you don't have enough storage space on your iPhone or iPad in iOS 12/11, you can't download or update apps. Therefore, check how much free space you have and free up iPhone space by deleting unwanted documents and apps.
Go to "Setting" > tap "General" > tap "About" > check "Available" to see how much free space you have.
If there is little available storage on your device, you can free iPhone space by exporting unwanted iPhone files or deleting some data you don't need, like apps, photos, podcasts, or videos.
Fix 6. Restart Your iPhone/iPad
If the app appears on your Home screen, but is dim or has white with lines on it, don't delete the app. Restart your device, then go to the App Store and redownload the app.
How to restart your device: press and hold down the sleep/wake button until the slider appears at the top of the screen, slide right to turn it off. After nearly 30 seconds, hold down the sleep/wake button again to restart your iPhone/iPad.
Fix 7. Set Date and Time Automatically
iPhone's date and time settings can influence the apps' downloading and updating in iOS. Therefore, set your date and time to be automatically to solve this problem.
Go to "Settings" > tap "General" > tap "Date & Time" > slide to turn on "Set Automatically".
Fix 8. Update to the Latest iOS
Another common solution to many problems is to update to the latest version of the iOS, which may solve the issue caused by system bugs.
Go to "Settings" > "General" > "Software Update" > check if there is a new version available, if yes, download and install it on your device.