For web purchases: You should login to your account in Muslim Assistant app with the email address you made the purchase with. Please follow App Settings > Join Muslim Assistant or My Profile > Login steps.
For purchases made inside the app through Apple or Google: Please tap “three dots” on the corner of homescreen then tap “Restore”.
Check your email address
The most common answer to being locked out of your subscription is to check that you’re logged in using the right email address. (This is especially true if you're being asked to pay again). Make sure you’re using the email you registered with, and you can always check your email to see if it contains a welcome email from when you first joined. And you can request new password on the login screen.