Getting halfway house time credited toward a prison sentence requires a formal legal process and cannot be accomplished through a simple phone call to the facility or the court.
The correct path is filing a motion with the court requesting a hearing specifically to address the time credit issue. That motion needs to lay out the legal basis for why the halfway house time should count toward the sentence, cite the relevant statutes or case law that support the argument, and request that the court schedule a hearing to rule on it. This is legal work that requires someone who knows how to navigate the court's filing requirements and procedural rules.
An attorney is the right person to handle this. If the issue stems from a government error in calculating or applying sentence credits, your inmate may be entitled to free legal representation to address that error. Federal public defenders and some legal aid organizations handle sentence calculation disputes, particularly when the Bureau of Prisons or a state DOC has misapplied the rules.
The first step is having an attorney review the sentencing documents, the judgment and commitment order, and any records of the halfway house placement to determine whether a legitimate legal argument exists for crediting that time. If the argument is sound, the attorney drafts and files the motion and the court schedules a hearing.
Do not attempt to navigate this without legal representation. An improperly filed motion or a hearing where your inmate is unrepresented puts them at a significant disadvantage on a matter that directly affects their release date.