Pulling SAM names from a CSV to see if they exist

I'm trying to import a csv of sam account names and then check AD to see if they exists. Currently when the program runs it tells me that none of the users in the csv are in AD, "'@{user=joe}' does not exist in AD"; Joe does exist. The only thing that populates the results.csv is the following:

TYPE System.String

Length 34

Import-Module ActiveDirectory

ForEach ($user in Import-Csv 'C:\users2.csv')

{ 
    $list = Get-Aduser -Filter "sAMAccountName -eq '$user'" 
    If ($list -eq $Null) {"'$user' does not exist in AD"}
    else  {"User found in AD '$user'" |
    Export-Csv 'C:\results.csv' }
}