Nasty Persistent Staff, even after various NO's!!!

These people contacted us and sold us which was according to them some amazing cartridges. The cartridges was supposed to last months. They were slightly cheaper than our current supplier and we decided to test them. The other cartridges normally lasted us a month or so. After two weeks the cartridge from them had to be replaced making it more expensive than our original cartridges. We haven't ordered from them again but boy are they persistent. The lady keeps on phoning wanting to speak to my MD and when I say he isn't the person to speak to she gets nasty. When I explain to her that this person is the MD and really doesn't have the time to worry about cartridges she gets even more nasty. I then transfer her to our buying department and the buying department doesn't even want to talk to her anymore. She is so persistent trying to sell her cartridges and when we doesn't seem to want, she gets nasty. I will never deal with this company again.