Anyone ever changed their eurostar ticks?

[Cdaniels1987]

Ok so as im sure most of you are aware i am taking my fiancee for her birthday for a short 3 night break however i have just had a nice little increase on my credit card so i want to try and extend my stay, i emailed eurostar explaining that i understand i have non exchabgeable tickets, but that i was taking my fiancee away for her bday and that i know the next day was only £20 more on the same train but they flatly refused saying id have to purchase a new 1 way ticket for.... £170!!! I only payed £130 for our whole return ticket!

Now heres 1 thing i am confused about if i try and book a whole new return ticket the return portion is coming up at £88 on an indirect train, however when i try and just book a single it says sold out on everything but the direct which is £170 as the chap told me!

I know that its my fauly for booking non exchangeable ticks but i work for a national coach company and although we say the same thing we will still change the ticks for soe circumstances!! i even pleaded stating that i booked the wrong ticket by mistake and that i want to get her birthday perfect but nothing no offer of help!!

Is there anything else i can try? Has anyone managed to grt theirz changed before? I am more than happy to pay the difference!