We did a mistake by booking our train tickets and noticed it immediately after the booking. We got in touch with the customer service immediately to inform them and to undo the mistake and to change the tickets. They informed us that there are options to change the booked journey and gave us an email to inform the responsible department about our situation. We waited quite a time to get a response as the journey was about to take place a few days later. We called again 2 days later and then we were adviced that the customer service was not able to help us and gave us another email address. We asked for the manager but we were not allowed to speak to the manager. We received then an email as a response from our first email that they were not able to undo the mistake (even if we informed Trainline 1 minute after booking). We were left with all the costs and no tiny bit of sympathy for our special situation which we explained and why we did, unfortunately, did the mistake. The customer service is not supportive at all. Trainline offers cheap tickets, but just don't make any mistakes because if you ever need the support of the company you don't get it. It is human to do mistakes, but Trainline seems to count on this to make money out of it.