Called and offered a toner cartridge for HP 4250 for trial use. We received the cartridge, but did not use it. Received an invoice. I called and was told that the toner was for trial use and to disregard the invoice. The company would follow up to see how we liked the toner. Several months later we received a phone call from Ann Turner with National Imaging Systems, Inc. stating that we had an outstanding invoice. I told her of my previous phone calls and she had no records of either of my phone calls. She was extremely rude. She later faxed an additional invoice. She stated that the conditions of receipt of the cartridge were fully explained, that it was an open invoice. That is not true, just the opposite was explained to me.