Record the purchase date, seller’s details, product fault, how it was used, and the remedy you want, and keep your receipt, photos and messages. Under the Consumer Rights Act 2015, goods must be satisfactory quality, fit for purpose and as described; you may usually have a short-term right to reject faulty goods within 30 days. After that, the seller will generally have an opportunity to repair or replace them before a refund or price reduction is considered, depending on the circumstances. Contact the seller in writing, and check Citizens Advice or GOV.UK if they refuse to help.