The Kelly Group Inc , Kelly Printing Supplies is trying to force-feed me toner cartridges! Las Vegas, Nevada

I received a cold call from one of their sales reps a few months back - he offered to send me a rather expensive toner cartridge - $90 -  for my laser printer.  He justified the cost by claiming that it lasted twice as long as regular cartridges, and offered a money-back guarantee if I was not satisfied.  I accepted, and paid for one cartridge. 
About a month later, I received another call from a rep letting me know that they were sending the 'other two cartridges I had agreed to buy.'  Since I'd never agreed to purchase more than one cartridge, I said as much to the rep, who seemed surprised but conceded that I was not under any obligation to buy more cartridges.
Now I am receiving calls every day from them - not only do they claim I agreed to buy two more, they are saying that I agreed to buy them at over $130 each!  I never agreed to buy more than one cartridge.  I would never have made a commitment to buy such a grossly overpriced product, let alone two.  For them to use these sneaky, underhanded sales tactics is poor business at best and a recipe for a lawsuit at worst.