Hi Guilherme,
I can not provide a direct answer to your question, but we have been using our own powershell script to perform the same.
The main reason we used our own PowerShell script as changing a primary email-address requires to turn off the EmailAddressPolicy on Exchange online. Which is not done using the ‘normal’ commands used by the IQService.
Set-RemoteMailbox $UserPrincipalName -ErrorAction Stop -EmailAddressPolicyEnabled:$FALSE
For some hints take a look at:
- Running Powershell directly via the IQService - Compass
- Issues running Remote powershell after upgrading from 8.0->8.3p3
If you have additional questions, we are here to help 
– Remold