What command?
Post the script you're using.
I think you'd be better off using a CSV file (just export the contents of the Excel file) than dealing with Excel automation to get the data.
Something like this can be used as a model:
import-csv <your-file-name-here> |
ForEach-Object{
$ReplaceParams = @{
DisplayName = $_."Display Name"
UPN = $_.UPN
etc.
etc.
}
Set-ADUser -Identity $_.Identity -Replace $ReplaceParams
}