@Robert Van Brunt made a post Understanding your 8x8 billing which is a good place to start. It also links to a helpful video which breaks down each section of the bill.
Looking at my own invoice and interpreting this, my understanding is that service charges relate to the services which you subscribe to from 8x8.
In the section under Existing Service charges is where you'll find additional detail about a given service.
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Jahmal Abbott
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