If you can see Praktika in your phone’s subscription settings, don’t worry - you do have access. Please try these steps:
Open the Praktika app
Sign with with your Apple, Google or Email account
Tap on Profile
Tap on the ⚙️ (gear) icon in the top right corner of the screen
Tap on "Manage subscription"
Tap on "Restore past purchases"
Wait for confirmation
You should now have access to Praktika Premium.