Contract cancellation reply e-mail does not exist. How can I cancel my subscription?

Hi, I am trying to cancel my internet subscription and I received an email asking for further details. I followed the instructions on the email (it asked for full address details, name/surname, date of birth and last 3 numbers of bank account number in PDF format). However my email does not send because the KPN email appears invalid. 
 

I am instructed to send the pdf to: ****************

but this email does not exist.

Where else can I send the proof? I need to cancel my internet ASAP, and submitted everything I need for the cancellation weeks ago.

thanks in advance 

*Admin: e-mail address removed