I tried to book online train tickets to Edinburgh through The Trainline. I was unable to verify my credit card details two days running so booked directly through South West Trains. I then received a confirmation email from Trainline even though I did not "confirm" my booking. I now have two sets of tickets costing more than £100 each. Trainline says it can't find the booking reference and, despite sending frequent emails, nothing happens. MLT-B, Batcombe, SomersetThe Trainline says you encountered a "technical error" when verifying your credit card details. The on-screen message said payment had not been authorised, although it had. It has refunded the cost of one set of tickets and added £10 to apologise. It described this as an isolated incident, but other readers have had difficulties confirming purchases through Verified by Visa. Like most of them, you bank with First Direct. Clearly something is going wrong and one weakness occurs to me: banks can still choose to allow payment even after Verified by Visa flags a refusal although. Customers are unaware of this until they find multiple sums debited from their bank accounts. I would like to hear from anyone who has encountered this problem. • Email Margaret Dibben at your.problems@observer.co.uk or write to Margaret Dibben, Your Problems, The Observer, Kings Place, 90 York Way, London N1 9GU and include a telephone number. Do not enclose SAEs or original documents. Letters are selected for publication and we cannot give personal replies. The newspaper accepts no legal responsibility for advice.