Honestly this is just crazy! Why would someone wait for 30 days before getting paid for a review that might not even worth up to $10. Your account is new and I hope you would explain more about this review of a thing and how much is the pay so we can know if it would worth the stay.
Although paying a reviewer 30 days after work is accomplished is absolutely absurd and I don't think anyone would do that when the pay does not worth the waiting.
Google play review only take between 2 to 5 days to be visible publicly and I don't see any reason why a reviewer would have to wait for that long before getting paid.