UPDATE :

Contacted by Technimo/ iReal Pro directly. Helpful in attempting to solve the problem. Though, there was no resolution. Directed to Google Play Store/ Customer Support. Very helpful, though solutions are somewhat useless, clearing data/ cache of certain apps. Still no resolution, even with being able to demonstrate method of payment (Google Play Store credit) and email account of transaction. The app has just gone missing/ does not show up anywhere.

Problem is : after hard reset of phone back to factory settings, iReal Pro goes missing from account of paid apps for reinstall.