You may petition for an injunction against domestic violence (F.S. 741.28/741.30) if he is related to you by marriage or adoption. Otherwise, you can petition for an injunction against repeat violence (F.S. 784.046). The theory of prosecution rests upon the offense of stalking (F.S. 784.048), which is repeatedly harrassing someone without a legitimate purpose, causing substantial emotional stress. You don't need an attorney to petition for an injunction, and there is no cost for filing. You would want to list the date/time of each phone call/test and the content of each, or print the text conversations and attach them to your petition. Even if the court did not grant a final injunction, summoning your step-father to court may persuade him to think carefully about his conduct in the future.