Who I have the same questioned this topic

I play one particular game that I downloaded from the Play Store and if  I'm ever purchasing anything in-app (in this case, units, gold etc) the it  always gives me "Bill my Verizon Account" as an option but it seems like I'm limited to about ten US dollars via that route. I need that amount raised to around $30 if possible. How do I go about getting that amount changed?