BAD PRODUCT

On the 27th of April I bought a GENESIS CORDLESS SWEEP at Verimark Garden Route Mall. On Sunday 27th of May, I assemble the sweep and put on charge till Sunday, the 28th. I took it off the charger and tried to switch on, but nothing was happening. I took it back to the store where it was purchased. the technician tests it and found that the battery was faulty. The day I went to the store, i didn't had my slip with me and they want to replace a new item with an old demo item. I don't want a demo item because i paid for a new item and I think no one will be satisfied to get his / her item replaced with an old secondhanded product. I also have no faith in that product and that it will ever work. I'd rather want a refund on.