How to reconnect?

Hi there,

 I got a Server 2012 R2 inside a VM in Azure. Unfortunatelly, I turned off the Firewall service, and now I'm not able to connect via RDP. Okay, this is logical.

But now, I don't know how to restart the Firewall service, 'cause I cannot connect to the computer.

Maybe via PowerShell? But I don't know really how, because this is not working:

Get-WmiObject -computer computer_name Win32_Service -Filter "Name='Alerter'" | Start-Service
Any kind of help will be very helpful.
Thanks in advance.