MB1234 - As you explained, it seems you did it right. I see no problems in checking with CPP-O by e-mail; but i doubt they may respond to this question specifically. I tried doing so several times after paying my RPRF and never got any response. The only place where i found regarding RPRF payment status is on GCMS notes.
But like i said feel free to shoot an e-mail to CPP-O; make sure you send an e-mail with all the required details such as:
1. Surname (last name)– Exactly as it appears on the passport or identity document
2. Given name(s) (first name)– Exactly as it appears on the passport or identity document
3. Date of birth (YYYY-MM-DD)
4. Unique Client Identifier (UCI) number / Client ID number
5. Application number ( F#, EP#, E#, B#)
6. Type of application (Family Sponsorship, Canadian Experience Class, Provincial Nominee, Quebec Skilled Worker
Hope this helps !!!