Linking is more of a nice to have than a necessity as you can see status changes such as medical passed and background checks in progress.
Do you still have copies of your application? The birthplace is usually the easiest to use and should match exactly how you inputted it in your application. Some people have reported success with placing a space before or after the birthplace. You get 5 attempts every 24 hours so it's worth a shot.
Failing that you can send a webform off to CIC and request technical help:
http://www.cic.gc.ca/english/contacts/web-form.asp