So Trainline have got back to me with the following:
I am sorry to know that your tickets were activated earlier and you had to purchase new tickets in order to travelled.
Under the booking reference number 440865754104 you have booked Off-Peak Return tickets travelling from:-
I wish to inform you that the ticket that you have booked is a refundable ticket subject to less £10.00 admin fee, however an activated tickets are considered to be a used tickets and therefore I regret to inform you that we are unable to request a refund on a activated ticket.
I would like to inform you that our application also warns you before activating the tickets. Please find the below mentioned screen-shot:-
I also wish to inform you that currently we do not have any reported bugs on our application or on the web-site. As you have mentioned that the station staff may have activated the tickets then you may have to contact them. However in order to help you with the contact details could you please confirm what was the name of the train operating company that was managing that station.