changing dates on flight booking

Hi folks, i have a question regarding the cost of changing my dates on a flight. I booked a return flight to england for the 15th of feb with BMI but a few days later i had to change my plans and book it for the 15th of march.When i contacted BMI i was told that the cost of changing the booking was £200!!! Because i had no choice in the matter i had to pay up to book my new flight, i paid by VISA for all the flights.Can i have any claim back any for the cost of changing from my credit card?

Why would you be able to claim back? Clearly says on their web site they can charge you for changes.

http://www.flybmi.com/bmi/en-ie/legal/website-terms-and-conditions.aspx
Changes to tickets
On UK Domestic and Western Europe bmi operated routes where a change fee applies, you may change the date and time of your flight before departure for £30/€45 per person, per sector, per change. On applicable shorthaul routes you can make changes to your booking online via 'Manage my booking'.

Changes are subject to availability of same class or plus payment of any upgrade fare. For all other routes where online changes are not possible and codeshare routes, this rule does not apply and you should refer to the individual fare rules during the booking process.