Importing Opt-Out Entries

curl -X 'POST' \
  'https://webexpress.retarus.com/PicoPortal/autoLogin/listImport/' \
  -H 'accept: text/plain' \
  -H 'Content-Type: multipart/form-data' \
  -F 'j_username=user' \
  -F 'j_password=password' \
  -F 'dlu_type=blacklist' \
  -F 'dlu_listname=Name Opt-Out list'  \
  -F 'dlu_listcomment=Comment for the Opt-Out list' \
  -F 'dlu_defaultcountrycode=+49' \
  -F 'dlu_firstrowcolumnnames=on' \
  -F 'dlu_charset=UTF-8' \
  -F 'dlu_file=@Test-Upload.csv;type=text/csv'

$Uri = 'https://webexpress.retarus.com/PicoPortal/autoLogin/listImport/'

$Form = [ordered]@{j_username = "user";
    j_password                = "password";
    dlu_listname              = 'Test-Upload.csv';
    dlu_charset               = 'UTF-8';
    dlu_defaultcountrycode    = '+49';
    dlu_firstrowcolumnnames   = 'on';
    dlu_type                  = "blacklist";
    dlu_listcomment           = "the Opt-Out list";
    dlu_file                  = Get-Item -Path  "./testblacklist.csv"
}
$Result = Invoke-WebRequest -Uri $Uri -Method Post -Form $Form