Kelly Printing Supplies Very shady business Las vegas Nevada

This company repeatably calls us after we asked them to stop. I think it's happened 5 times know. They're way too pushy. I finally agreed to 1 black ink & 3 color ink cartridge for my printer. I received 2 black and 3 color. Then charged a higher price for half full junk cartridges. She explained to me that they have a cartridge that would last longer. etc. She told me that I had no obligation to purchase and that I had 6 months to try and if I didn't like it send it back.I received a call from  from Kelly Printing Supplies wondering why I haven't paid their invoice. I told her I haven't' paid it due to the fact I have not even opened the box. They told me I still had to pay for it. I don't believe I should pay for something I haven't even used tried yet.