Adding Users Devices to a Collection by First and Last Name

Recently I was given a Set of User's Names to exclude from a deployment. Easy. Until I realized the deployment was deployed to devices, not users. I dropped the user list into a text file. First Last, each on its own line. I read the file and grabbed the username, then performed a User Device affinity check, throwing the associated computer into the exclusion collection.

$collectionname="Exclude Reader DC"

foreach ($x in gc C:\temp\adobe.txt){
$y=get-qaduser $x
$user="DOMAIN\"+$y.samaccountname
$z=Get-CMUserDeviceAffinity -UserName $user
#$q=Get-CMDevice -ResourceId $z.resourceid
#$q.name
$z.resourceid 
 Add-CMDeviceCollectionDirectMembershipRule -CollectionName $collectionname -ResourceId $z.resourceid   
}