I’m confused about CPD – and the college is demanding money

I’m confused.
I am a vocationally registered GP (therefore entitled to access higher Medicare rebates) and am not a member of the RACGP. My AHPRA status is as a specialist and a generalist GP.
Last week, I received an email from the RACGP asking me to log on to their website and download my invoice for CPD Participation from 1 January to 31 December this year.
The amount due is $945.