You should file for disclosure immediately, and show due diligence. On the day of your trial, speak to the prosecutor prior and explain that you were only notified of your trial after personally checking in with the court, as no mailed notice was received, and therefore there was no adequate time frame for them to provide disclosure. In a situation like yours it is quite understandable that you would be filing for disclosure at such a late time. The prosecutor at this point can choose to A:) Withdraw the charges B:) Request an adjournment from the Justice because of institutional error or C:) Tell you "Tough luck" and proceed to trial.
Option A: is best possible outcome. No trial occurs.
Option B: is a good outcome. You should remember that you would, in a case like this, reiterate to the Justice that you are not Waiving Your Rights, and due to institutional error cannot take the blame for the adjournment.
Option C: is the worst outcome. You should try and find some case law supporting your argument, which will be that: Due to an error in notification of the trial date at the court's fault, you were unable to request disclosure in a respectable time-frame. You will show that you did request for disclosure as soon as you received you Notice of Trial (via fax is recommended) after attending court to check. It is an unfortunate circumstance, but in no way are you waiving your rights or blaming the Prosecution. This is an institutional error, and the only means of preserving the process is to grant an adjournment. Remember that your right to disclosure is a Charter mandated one. We also have what's called an adversarial system, so by speaking to the Prosecutor about the circumstances you again show due diligence with regards to figuring the situation out and trying to find a solution prior to entering the court room.
Good luck.