Script to import GAL into Contact Folder

Hi,

I'm using this script to copy GAL contacts to a contact folder in some mailbox users.

https://gallery.technet.microsoft.com/scriptcenter/Importing-Global-Address-dc52a0ce

This script, search for a folder in contacts folder of user mailbox. If found, empty it, if not found, creates it. Once done whatever, begins to create contacts from GAL into the folder.

But I need not to empty the folder if exists, but check if the contact taken from the GAL exists in the folder. if not, create it; if exists, overwrite Name and Surname, telephone number and email address, leaving all other data without change.

I am not a Powershell EWS expert, and I don't know how to afford this. I have been searching a way to find and modify contacts, with no luck.

Could somebody help me?

Thanks