I do not travel regularly on trains and this was my first time travelling solo on a long distance journey. I purchased a m ticket through Virgin Trains from Glasgow to Grantham on Saturday 13th July 2019 and returned Monday on 15th July 2019. I downloaded the app could see both tickets. On boarding the outward bound train I activated the ticket through the app but had problems getting on the internet but eventually it downloaded and it scanned successfully. Mindful of this I decided to activate the m ticket on Sunday evening at approx 11pm as I had WiFi available. Thinking it would alleviate any stress for my return journey . On the Monday I boarded the first train from Grantham to Leeds and was asked for my ticket. I presented my ticket and the operative went to scan it. He indicated it was not a valid ticket and after a quick conversation it became apparent that i had activated the ticket the night before and this is why it appeared invalid. He said this happens sometimes but manually processed my ticket. I raised my concern about getting on the Leeds to Glasgow train but assured me I should be fine. Got to Leeds and boarded train. I explained to the operative what had happened and she said she would need to send a report as my ticket was not valid. ironically I had a seat reserved for me by Virgin on this extremely busy train.Approx 6 weeks later I received the 1st letter from TIL, standard letter, possibility of being taken to court, asked to send in my mitigating circumstances which I duly did, via email. I send them screen prints of my m tickets, booking confirmation and credit card statement. Received 2nd letter, again a standard letter, intimating that if I paid a £65 admin fee there would be no further action. Phoned the company requesting to speak to an agent to get clarity as this was at standard letter giving no explanation. They are contactless by phone and advised to send another email and received a letter indicating that my ticket was invalid as I had activated it the day before and therefore the admin charge applies. I have looked at the t & c on the confrontation email I received from virgin and it stated please ensure you activate your m ticket before you board the train but nothing about there being a specific time guideline. On further investigation, numerous googling, I have since managed to find, in small print, the clause about activating it on the exact day. Is there any other avenue to pursue to try and right off the charge or do I just pay it and put it down to a lesson learned. Thanks in advance for advice and guidance.