Help with major ticket refund problem

I booked a LX (Swiss) flight directly on lufthansa.co.uk to fly from CDG-ZRH. I wanted a fully flexible ticket so I could refund if my plans changed. I read the fare conditions (see below) before booking as I always normally do.

The fare that you have selected is fully flexible and can be rebooked and cancelled free of charge.

Please note that your ticket has to be flown and completed in coupon sequence with the booked routing as entered. Failure to observe this rule will invalidate the ticket and will then no longer be accepted for transportation.

For further Information about the fare conditions please call the Lufthansa Service Center in Germany at 01803 - 33 66 33 (€0.09/min. from the Deutsche Telekom landline network; call charges may vary dependent upon network operator or mobile network provider).

Yesterday I checked-in at the airport an hour and a half before departure but a last minute change of plans meant I couldn't fly and had to return to London. I asked to be off-loaded from the flight. Today I called LH to request a refund and was advised my ticket can only be refunded before departure. At no time was this mentioned when I booked my flight nor when I called Lufthansa in the UK immediately after booking to confirm that my fare was fully flexible and refundable. Fare class is D so I was aware when I booked that there might be some restrictions so called to check - agent confirmed it was a refundable flight but never mentioned only before departure.

I have been advised to write in a complaint which I will do. Do I have a good chance of disputing this with my credit card company if Lufthansa does not resolve this to my liking?

[Scrooge]

I would dispute it, fully refundable is fully refundable.

When I booked on lufthansa.co.uk I ticked the box to request a flexible fare.

The system will calculate the lowest price for the selected flights. This price might have certain restrictions in regard to changes and cancellations. Should you require a more flexible fare please mark the field below.
Click for flexible conditions

As I said, at no time was I made aware either online or on the phone that my ticket could only be cancelled and refunded before departure. Which was why I only asked to be offloeaded from the flight. I didn't even ask to change my flight for another date or request a refund there and then as I was in a hurry because I just wanted to get back to Paris to catch the Eurostar to London.

Well, I called back and another agent confirmed that the fare was refundable after all. So I've absolutely no idea what the other agent was talking about.[?][?][?] Anyway, everything looks fine now.