Having trouble with character encoding when opening a .csv file either on excel or in numbers!

Hi.

I oftenly use internet banking services which produce .csv reports for the transactions i make. After downloading these reports i try to open them in numbers (and excel) but the encoding for Greek is messed up. Opening the same file with excel on a windows computer everything works fine. Is there something i can do to fix this?Same thing happens to both my Macbook Pro and my iMac.

Many thanks in advance,

John