Certain configuration steps done in a particular order will result in duplicate costs appearing in the platform for partner customers. Here is the process that likely took place:
Partner assigns Azure subscriptions to a customer via EA bill splitting.
Partner also configures the EA directly in the customers tenant.
Duplicate cost data will result.
Resolution
If the above process took place, the following actions are required to get the duplicate cost removed:
Remove either the EA directly configured in the customers tenant, or remove the subscriptions assigned via EA bill splitting.
Request that Technical Support retrigger/reprocess the EA usage for the affected month if the month is already final (current or un-finalized months will self-correct).