Bad service

We bought an HP laptop on the 2nd Feb, we dins start to use it immediately only after 2 weeks. Then its started giving us a screen saying your batterys been depleted and need replacement. It can not work if not on mains. So i went to Three Rivers and they said they need to send it in and will take 14 days. This laptop is used in a business and we can not sit without it for 14 days. Why does one buy something only to use it for 2 weeks