It's simple to undelete a user you have deleted in the GSuite control panel - so long as you recently deleted them.
From the cpanel, go to Users and select the Active users dropdown on the right hand side. Choose Recently deleted users to see a list of users that can be restored. If your user is not in this list they are lost and cannot be restored - contact our helpdesk if this is the case.
Step 1: choose recently deleted users from the dropdown
Step 2: select the user and click the undelete user icon