I have been a loyal Amex UK customer for over 10 years, but after my recent experience, I am now considering closing my account and transferring my business to another provider.As a Platinum Cardholder with an annual fee of £575, I expect a high level of service that reflects the premium nature of the product. However, my recent interactions with American Express UK customer service have been extremely frustrating and disappointing.On multiple occasions, I attempted to call your customer service line around 20:30 to make a payment and resolve an issue I was having with my online payment system. Despite calling five times and using various options, I found that all departments were closed, with no support available. This is completely unacceptable, especially for a premium service. It is particularly concerning that I could not even reach assistance during a time when it was crucial for me to make a payment.Furthermore, the inability to access customer support during non-business hours raises serious concerns about the reliability of your service. In the event that my card was lost or stolen, I would have had no immediate assistance, which is an incredibly important service that I expect from a premium card provider.Given these ongoing issues, I am now seriously considering cancelling my Platinum card and moving my business to either Barclays Premier or HSBC, as I no longer feel confident that American Express UK can meet my expectations for reliability and customer service.To anyone considering Amex UK, please avoid, it is not worth the yearly fee by no means.