A fake bank page appeared as i was trying to acess my bank account. The support attendant from the bank told me that i might have a trojan on my notebook and net.
Are you running wine? If so, try clearing out your virtual C drive. If you have one, it's incredibly unlikely it's anything but a Windows virus hijacking a wine installation. Linux viruses are exceptionally rare and those that do exist typically target the larger server based distributions rather than smaller desktop distributions.
I would say more than likely, you were the victim of a phishing scam. Ensure you only ever enter your bank log on information into the site if you've typed the site's URL directly into your browser and never when linked to it from another page or email. For more information, research the topic "online phishing".
If you are using Firefox , go into the preferences tab , then go safely tab and disable the last two boxes. This should solve your problem.
First what comes in mind when correctly entered URL leads to a fake page is DNS settings. Did you check if the same behavior is present when you're trying to connect to your bank URL from other devices on the same LAN? I'd check DNS settings on the router, modem and laptop to see if they were altered by someone.
Also don't ever trust green padlock next to your site URL - when connecting to something such important as a bank account I'd always check the server certificate and the issuer. Believe me, I experienced it myself at work where employer installed his own root CA to sniff encrypted communication... and there is always famous Lenovo scandal with SuperFish ;)