Contact the company as soon as possible, explain the problem clearly and say what outcome you are seeking, such as a repair, replacement, refund or other remedy. Keep receipts, photos, messages and notes of conversations, and check whether the Consumer Rights Act 2015 or the contract applies to your situation. If the first response is unsatisfactory, use the company’s formal complaints process and ask whether it belongs to an approved alternative dispute resolution scheme or an ombudsman service. Citizens Advice can explain your options, while a solicitor may be appropriate for a complicated or high-value dispute.