In general, if you've not received an error during delivery, we most certainly got your message... it may have even made it to the queue (if it wasn't already filtered by new rules).

One way to be sure we receive your spam is to create a pop3 box on your system for your spam submissions and provide us with the login data (email address (as login), password, FQDN of the pop3 server). This way, if the mail in that box gets deleted you know one of our bots has pulled it in and added it to our queues.