Hello, Diane -
Are you really asking about how to get your number unblocked from a person's cell phone or how to unblock someone else from calling your cell phone? Your question landed in the Fixya.com category for Cell Phones.
Or . . .are you asking for help regarding a criminal case - a legal question?
If yours is a cell phone question, only the individual/s blocking your phone number from calling their cell phone/s can unblock your number. If you are asking about how to unblock someone else from calling your cell phone, your cell phone provider probably has information how to do that or the manual for your phone has instructions on how to go about it.
This link gives directions for unblocking and blocking a phone number from a particular model of Samsung cell phone:
(TinyURL link): https://tinyurl.com/b72hys5
If you wish someone else to unblock your phone number from their cell phone, you will either need to ask them in person, send an email or message through Facebook or some other social networking site, or write a letter and send it via U.S. mail.
If yours is a legal question . .
Without knowing where you reside (what country? what state in the USA?) it is a challenge to provide you with the proper information and direction.
Wherever you reside, my advice is to seek legal counsel regarding the criminal case. In the USA, that means find and contact an attorney specializing in criminal law in your area. In the USA, most attorneys do not charge for an initial consultation.