Hi Paco,
Since everything in Office 365 Plan E1 is included in Office 365 Plan E3, if you haven’t brought E3 plan, you should be able to switch E1 plan to E3 plan using switch plan wizard.
For more detailed steps, please refer to: Switch to a different Office 365 plan or subscription.
If you cannot use this tool to switch plan directly, please feel free to post back, I will further help you.
In addition, when you said “through calling support”, do you mean you have submitted a service request or contacted the CPC team? If so, could you please provide the SR number for me?
To protect your privacy, I have sent you a private message to request the tenant information and the SR number. To access the private message, please follow the steps below:
1. Go to the your details section on the right side of the community site.
2. Click Private messages.
3. Click the subject title of the response to read the message.
4. You can reply by using the form in this display.
5. Click Submit Reply.
Best regards,
Jamie