Well, depending on what service you have. You can go to your account online and fix everything. I have t-mobile and I did it. But you need to know your password too.
How Do I Unblock Texting If My Parents Blocked It?
You have to call the phone company and ask them.
You parents would be mad if they found out you unblocked it. Find a part time job and help pay for the phone and then ask them to unblock it.