I don't do phone calls because of a disability, so when this happened to me I emailed P and O, explaining that I can't phone. They gave me the 28 day caper, so I raised a dispute with my bank and got the money refunded within 3 days. P and O later apologised by email after they had investigated. Always use a credit rather than debit card, as it's the quickest way to get your money back, and can all be done online.