How to change the display name of a bulk of shared mailboxes?

Hi guys,
I have to rename a bulk of shared mailboxes to a new format, the script is ready and works but when the script runs, the names that contains accentuation are not being updated properly and a question mark is shown where the accentuation should exist.


-----------------------------------------input file:
name,NewName
BMS-cipatubarao,"CIPA Tubarão"
BEL-liberacaeodelimbo-amd,"Liberação AMD"

-----------------------------------------Script:
$sharedChange = Import-Csv .\"SHAREDchange.csv"
$sharedChange | foreach{
      $sharedName = $_.name
      $sharedNewName = $_.newname
      try {
      # Change the DisplayName on Services Domain
            set-user $sharedname -displayname $sharedNewName
            "$(get-date -f MM/dd/yyyy-HH:mm:ss), $sharednewname, modified on, $sharedname`n" | out-file '.\SharedSuccess.txt' -append
      }      catch {
            "$(get-date -f MM/dd/yyyy-HH:mm:ss), $sharednewname, NOT modified on, $sharedname`n" | out-file '.\SharedFailed.txt' -append
      }
}
-----------------------------------------output file:
09/04/2017-17:47:12, CIPA Tubar�o, modified on, cipatubarao
09/04/2017-17:47:14, Libera��o AMD, modified on, liberacaeo-amd

What should I do?
I have already tried to use the command directly on my shell using set-mailbox liberacaeo-amd -displayname "Liberação AMD" and it works, but as I have a batch of shared mailboxes to execute this change, this is completely out of  question.