Source: http://www.cic.gc.ca/english/resources/tools/fees/imm/rprf.asp
Timing of payment
Payment of the RPRF will be required before issuance of the permanent resident visa for applications processed at visa offices or the permanent resident record for applicants in Canada. Each contact with the applicant should include a reminder that the RPRF is required, and that the visa will not be issued or the client will not become a permanent resident, as the case may be, until payment is received. It should also be emphasized that early payment of the RPRF will avoid delays in finalizing the processing of the application for those classes where it is appropriate, such as priority family class cases. Other cases, such as family class sponsorships of parents and grandparents, where the processing time is known to be long, RPRF instructions specify that the client should wait to pay RPRF until contacted by CIC.
Although concerted efforts will be made to solicit payment at the early stages of processing, CIC must accept payment of the RPRF whenever it is submitted. This is a requirement of the Financial Administration Act. CIC also has no authority to refuse to refund the RPRF upon request of a client who has paid up front or at any time before the RPRF is due for visa issuance/permanent residence status. This is a change to the past policy that RPRF payments already submitted for applications in process will not be refunded, unless the application is refused or withdrawn, or does not result in permanent residence status being granted.
Should a client complete all other documentary and regulatory requirements for acquiring permanent resident status but fail to pay the RPRF and complete the acquisition of permanent residence process, there is no legal basis for closing the file or regarding it as abandoned.