Public services are being increasingly scrutinised for their ability to be responsive and adaptive to their service users' needs. For service delivery in domestic violence, many aspire to include feedback from service users on their practice, to drive change in their organisation and performance. Current approaches for capturing and using feedback (i.e. surveys) often fail to record rich, in-depth perspectives that audio-video media affords. In this paper, we present the novel application of a voice-based technology to capture and use feedback to reflect on the delivery of a domestic violence intervention. Across four months, we undertook ethnographic fieldwork through observations of four deployments and four reflective discussions with service-staff in their delivery of a novel domestic violence prevention intervention for violent men. Our findings highlight the tensions with how voice can act as a resource to reflect on and refine existing service practices, and offers insights into how technology can play a more practical role in wider service design.