NO MOVING PARTS!

I bought a pricing gun from Rite Mart for R200 a month ago. The gun included one roll of paper and no ink. The gun had the ink already. A month later, i go back for more rolls of paper to put in the gun. They didnt have any in stock and said they would order some more and advised that Fikelelo would call me on Saturday if they have the rolls. They did not call. They eventually called on Monday to say they are unable to get the rolls. I then called them and told them I would go elsewhere to find rolls and if I couldnt find them, I will return the gun. Fikelelo then told me I can't return the gun because it has already been used. How can a store sell a product if they do not have the parts that go with it???? And then refuse to take it back because it is now useless. I am a pensioner, trying to sell odds and ends to make extra money. R200 is a lot of money to waste on products that are useless after a month.