@Linus Cansby We bills our customers for toll telephone service which would fall under the law. We must retain this information for toll calls that we bills whether it is billing our own toll service customers for toll calls or billing customers for another carrier.

While you mentioned a Teams to Teams call is free, an internal call where users have an enterprise voice number is not free as we 1) charge back for voice service if a user has a phone number and 2) licensing for Teams voice is not free. I also hesitate for anyone to say Teams is "free" in general as any service has licensing costs. 

Even in a Direct Routing scenario we still need to get the internal Teams to Teams calls if the user is licensed for voice and has a DID.

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