Start by checking your council’s decision letter, which should explain why your Council Tax Support was changed or refused and how to challenge it. Ask the council to review the decision, including any evidence that supports your circumstances, and keep copies of everything you send. If you remain dissatisfied, the next appeal route depends on where you live—for example, the Valuation Tribunal for England handles many English Council Tax Reduction appeals. Check your council’s guidance or the relevant official tribunal website for deadlines and procedures.