Faulty equipment

I had purchased a brand new sub from sound match parrow on 18/01/2016. I was told the sub would be able to handle the setup in my vehicle. I was then told that there would be no guarantee? I asked why if they guaranteed it would be able to handle the setup. After installing it 30 minutes later it blew. I went back to the store where one of their employees clearly stated that there is always one in stock with a defect. No guarantee yet they knew it was faulty does this still go unde the CPA? No offer to repair either. Just terrible service