Worst service provider I have ever used

Supersonic failed to render invoices for four months straight. I informed them of the error telephonically and via email. Never received the courtesy of a response or an apology for the error. After a final email wherein I again informed them of the error, I suddenly get a massive account and they expect me to settle it in one month. I'm curious as to what would've happened had I not informed them of their own error. Would not recommend them to my worst enemy.