count the number of unique values given certain conditions

I've searched through the forums to see if my question was already out there and i feel that so many posts were so close but i couldn't wrap my head around how to make them work to my situation. I've never used =FREQUENCY or =MATCH formulas so i have no idea how to manipulate them for my needs. (i saw these being used in similar posts).

here's my specific problem. i need to count the number of unique phone numbers for outbound calls in August by each person. so i have 4 columns of information, 3 columns of criteria, and the 4th column is the list of phone numbers.

i've attached my sample data with the results i'm looking for and an explanation of the desired results. i hope someone out there gets what i'm trying to do. i hope i was clear enough! fingers crossed that there's a solution.

Erin