You're up early!

Try this formula: I made an assumption that since these are dollar
values, they may not always be integers (whole dollars) so the formula
checks for less than $5, between $5 and $11, and over $11. Let me know
what you think.

=IF(A1<5,"Send letter",IF(AND(A15,A1<11),"Phone call","In-Person
Mtg"))