And I’ve always found the CIPAV website next to useless - sometimes the “documents” are there and at others they are not, what a palaver. I probably won’t be sorry to see it go if it means that I get a decent informative website to replace it, but I’m not holding my breath…
A useful explanation of what the CIPAV is/does, and the levels of cotisation can be found here:
https://www.lecoindesentrepreneurs.fr/affiliation-et-cotisations-a-la-cipav/
and I thought the RSI was bad…! 
Well at least you got a reply Anna ! 
My own experience of the CIPAV hotline is less than glorious - sullen, and unwilling to advise. Having said that, compared to the RSI, which for me is in Bourges (a mere 2 hours drive away), the CIPAV is an up-there-fully-communicative organisation. Getting anything useful (like EU health card) from them other than how much I owe each “trimestre” is tantamount to a pilgrimage in the middle ages (“la croix et la bannière” as the French are wont to say).
On the phone I did get an answer, although the conversation started with me being told that I shouldn’t need to be asking the question because the information had been sent to me in the post ages ago (it hadn’t) and I should have kept the letter. Emails using the contact form on the website invariably vanish into a black hole.