If you always have valid numbers in 'Number' column, then you can shorten the formula to;

=SUM(IF(FREQUENCY(IF((A$2:A$61=F2)*(B$2:B$61=G$1)*(C$2:C$61="Outbound"),D$2:D$61),D$2:D$61),1))
F2 = Name, ie Angela
G1 = Month, ie August