show unique locations or account # by month

I have a list of accounts ~6500 rows of data.

it shows accounts listed by "account # - column D" and "address - column F".

I require a formula (not pivot table) In cell Z2 i want to show "unique" list of locations by EACH MONTH that occur only once, so i can calculate their revenue. For example, ABC Inc may be serviced 3 times in a month, however i want to show the value for the "first" service that occured for that month.

THerefore, my criterias are
Month = column S
Category = "auto" column T
Unique address = column F or use column D (account #)

i have been stuck on this and dont know where to go. any help will be truly appreciated....thanking you in advance.