how can I do now?

Hi,Everyone,I got a problem about my sredit card,need your help.Last month I maild check to pay off my bill 5 days earlier to due day ( Dec 17th 2007) as before.But the mail got delaied 3 days for some reason ,perhaps due to the IL storm where I sent to.So they charge me late fee plus finace chagre.I called credit card company they won\'t take off the charges.But I still think its unfair to me.What can I do now?
Thanks