Yes they are accepting more than 5000. Because...
1) Paying fee doesn't mean you are successfully got selected for PNP.
2) Its non-refundable fee so they will not deny to any candidate to pay them (CAD) $757 for nothing at all.
If there are 42000 registration (according to what they claimed last time for this project) and out of this number... let say... only 10,000 candidates are paying to them... as prime-applicant. So now you can calculate how much they are earning within few hours
and I am sure the number of payees are more than 10,000.