The fact that you're crying to this forum about the temporary loss laptop is proof enough that you're addicted. Instead of spending your time scheming clever plans on how to get your laptop back and/or whore for attention, you could be studying math. I'm going to bet the reason your parents claim you're addicted is because of your grades. I'm going to assume that you rarely study or do your homework in math, which is why you're failing. Your parents see that you could be studying and maintaining your grades, yet you spend your time on the computer, which shows that you value your time on the computer more than your grades (and thereby your future). If you work on maintain good grades, which will take some effort resulting in considerably less free time, your parents won't question what you do in your free-time because you're showing that you can maintain good grades with your current lifestyle.
This is the exact situation I went through in middle/high school, it's not a good habit to have later on.