Auto-entrepreneur agent commerciale for estate agents?

I am working as an Agent Commerciale for a French estate agent. I did the online application because I am an agent commerciale, it sent me to the greffe website. The first problem I had was that I received a call from the tax office saying that it isn’t possible to be an auto-entrepreneur if you are a commercial agent for estate agents. However my boss and I found online evidence that this was OK.

To be eligible to be an auto entrepreneur you must be eligible for the regime fiscal micro BNC. This means that you are not attached to the RSI for your social charges but to the URSSAF. The key distinction being that your activity and thus your income is non commercial rather than commercial.

I then received the following paperwork. From the tax office confirming my Siret and that my regime was micro-entreprise and TVA was franchise en base. From INSEE confirming my registration. A lot of certificates from the greffe. I was all poised to do my first declaration and payment in October to URSSAF, when I received a letter from RSI saying I had affiliated to them. I have since received another letter from the RSI asking me to return some declarations to them. I am really confused, and don’t know who I should contact to sort this out. I am also aware that my first declaration is now overdue. Can you help? Is there any difference between being micro entreprise with RSI and auto-entrepreneur with URSSAF?