The prefix of my prefix is not real
My prefix was not declared real
My infix is basically natural
My suffix is everything else
And if you owe me, I'll come pounding at your door
What am I?
From the old Fortran joke:
GOD is Real, unless declared Integer (variable types in Fortran)
"Int" is the prefix, and "i" the prefix of the prefix. The base(-ically) natural is "e", and everything else is the "rest"
Making the answer:
Interest, which if owed, could lead to debt collectors at your door
This also fits nicely with the title, as:
"Tell me more about that" is displaying Interest