Santander Bank - compromised - Beware!

Was just trying to pay some credit cards online & was asked a mountain of security questions, gradually getting angrier & angrier, as it left you with this screen saying it was sending you a recipient number, whatever that is.

Eventually rang the bank & it turns out it was a fake website, so someone out there has all my personal details.

So awful, the bank is going to have to send new registration number & ID's but how do I change where I was born or went to school???