If you downloaded the datas as CSV, drag and drop the file on TextEdit's icon.
This way you will see the way values are stored.
If your system is set to use decimal period, Numbers requires values separated by commas in the CSV file
but
If your system is set to use decimal comma, Numbers requires values separated by semi-colons.
If the file doesn't match the rule, Numbers open the file with no error message but every values of a given row are inserted in a single cell.
So it seems clear that you didn't receive a csv datafile.
I'm, afraid that you downloaded datas for Excel or SDMX and give the file the .csv extension.
As I have no access to your bank, I can't guess what are the real format of the datas.
If I ask my own bank to download datas for Excel, I receive CA20120121_1223.slk
Numbers is unable to treat it correctly but one more time, it display its contents with no error message.
May you try to download in the three formats available ?
Then select one file's icon then press cmd + i
You will get the infos about the file.
Near the top, you will get the Type of file.
In the middle of the window you will see the "Open with" info
Do that for the three files and pass the info here (plus the used extension names).
Yvan KOENIG (VALLAURIS, France) samedi 21 janvier 2012
iMac 21”5, i7, 2.8 GHz, 12 Gbytes, 1 Tbytes, mac OS X 10.6.8 and 10.7.2
My Box account is : http://www.box.com/s/00qnssoyeq2xvc22ra4k
My iDisk is : http://public.me.com/koenigyvan