Distinct Count based on Multiple TRUE() conditions from 2 Columns

Hi all,

I have been unable to come up with a DAX Measure to caulclate a Distinct count of Customer IDs where 2 conditions are TRUE (). 

Below is a Customer ID where the 2 conditions are TRUE i.e. Pre-Paid Flag & Internet Flag are both True. I want to Distinct count all customer IDs in the table where these 2 values are TRUE. In the below case, ideally, the Measure would return 1 as this customer ID has TRUE on both Flags.

Below is the measure I've come up with but it does not return any count. It does return a count if I have only one condition as TRUE i.e. Pre-Paid Flag = TRUE () but not where bot conditions are TRUE ()

CALCULATE (
    DISTINCTCOUNT ( 'Account'[Customer id] ),
    'Service'[Pre-Paid Flag] = TRUE () && 'Service'[Internet Flag] = TRUE (),
    CROSSFILTER ( 'Subscription'[ACCOUNT_KEY], 'Account'[Account Key], BOTH ),
    CROSSFILTER ( 'Service'[SUBS_KEY], 'Subscription'[Subs Key], BOTH )
)

This is my Model view

Any help will be much appreciated! Thank you!