Abusers routinely use technology to spy on and harass their targets. This harmful behavior is known as technology-facilitated abuse, or tech abuse. Survivors of tech abuse may turn to the legal system for safety and security, and to do so, they need evidence of tech abuse. However, prior work indicates challenges to collecting evidence of tech abuse and using it in legal proceedings. Thus, in this work, we study legal evidence used by survivors of tech abuse in Wisconsin, USA. We report on qualitative interviews and focus groups with 19 legal support providers who work with survivors seeking protective orders, divorces, and criminal charges. Our findings surface current practices that survivors and legal support providers use to prepare and present evidence of tech abuse in Wisconsin and the challenges they face. For example, survivors struggle to collect evidence of covert monitoring and surveillance. When they can collect evidence, it is often difficult to connect that evidence to the abuser due to the anonymous nature of many forms of tech abuse. In court, evidence of tech abuse is frequently challenged and vulnerable to objections and counter-evidence. And at the end of a proceeding, it's not uncommon for a judge to determine that the tech abuse does not meet the statutes. Informed by these results, we encourage CSCW and HCI researchers to work towards designing and deploying sociotechnical solutions that support survivors' use of evidence, in careful collaboration with advocates, legal experts, and survivors.