rgd PPR and RPRF request...Please suggest!!!

[Nishad]

I have received my passport and RPRF request on 30th January 2012 and I need to send the required documents to NY office. The email that i received from CIC has mentioned that...

"For addresses in Canada:
Standard Procedure: The Consulate will return documents to addresses in Canada via U.S. Postal Service First Class Mail (Regular Mail).
Courier Service: Unless it is prepaid from a corporate account, we will not return your documents using ANY courier services (Fedex, UPS, DHL).
 This office does not acknowledge receipt of passports."

Can someone please suggest what should be the best way to send the passport to NY office... through Canada post or any courier service?
Below are my timelines...
 We received your application for permanent residence on June 6, 2011.
 We started processing your application on January 19, 2012.
 Medical results have been received. (Medical done on September 19th 2011)

Thanks so much...

[SenoritaBella]

You can send it through Canada post using an envelope with a tracking number. Did they ask for a return envelope?