For all those trying to link the application on GCKey:
Use this approach, it does not require any additional information from CIC. You just need the information that you already filled in the forms (I was able to find mine today using this approach). If your file is in the system you will be able to find it.
Select Category: Permanent Residence
Select Sub-Category: Family Class (Parent and grandparent)
For Application Detail Select: Family Name, Given Name and Date of Birth
Note: You need to put principal applicant's details here
For Applicant's Personal Details Select: Place of Birth
Note: You need to put principal applicant's details here
For Other Application Information:
Where does the applicant intend to live in Canada?
Note: You need to put principal applicant's details here
Number of family members, including the primary applicant, that are part of this application
For number of family members, the calculation is
your parents + you (sponsor) + co signer (if applicable), ignore kids in this count
e.g if you are sponsoring both parents and have a co-signer, the calculation is 2+1+1 = 4
Note:
Make sure the information is exactly the same as what you filled on forms, use scan copy of the forms you sent, if you have one. Form IMM 0008 has all the information that is required.
If you can't find your application using this information, your file is not in the system yet. You will have to wait, getting a temporary file number or anything else can't help you. Be patient, wait a couple of days and then try again
GOOD LUCK!! linking your application.