What can I do if I cannot gather everything IRCC wants before my procedural fairness letter deadline?

If you cannot realistically gather everything requested before the deadline in a procedural fairness letter, the first step is to request an extension from IRCC in writing, explaining specifically why more time is needed and how much would genuinely be enough. An extension is not guaranteed, but a clear, concrete request made well before the deadline is more likely to be considered than one made at the last minute or not at all.

If an extension is not granted, or there is no time left to seek one, it is far better to submit the strongest evidence you do have by the deadline, along with a clear explanation of what remains outstanding and why, than to submit nothing and let the deadline pass entirely. A partial, well-organized response addressing the specific concern raised is treated very differently from silence, since the letter exists precisely to give you a chance to respond to a specific concern before a decision is made.

Missing the deadline without any response at all generally leads to a decision based on the file as it stands, with the unaddressed concern working against the application.