Email address forwarding problem

I recently closed down the website and address through which my emails came, but my ISP is forwarding emails addressed there (anhidas@bridgecandc.com) to a different address (ahidas@sonic.net). Unfortunately, your emails are not being forwarded and I am not getting the considerable number of alerts I am signed up for. When I try to update/change my email address, it wants my current password, but that is no longer valid, it seems. At this point, I'm at a loss with what to do.