Unbelievable service at builders warehouse

I bought a chainsaw at builders warehouse and it didn't work. I took it back and they insisted on sending it on for repairs to ryobi. It took 21 days!! I got it back, asked for a report, which they couldn't provide. Could not tell me what was wrong. I took it home and it still doesn't work. I took it back the same day and they refuse to give me a refund. They want to send it back for a repair again, but I want my money back because I do not want this product. They now have my chainsaw because I had to leave it with them and they are not giving me my money back.