Who should I be paying social charges to?

Please can you point me in the right direction over what happens to social security contributions now I am registered as an auto-entrepreneur in France. We moved to France in 2007 and had been covered by the couverture maladie universelle (CMU). In January 2012, I registered as an auto-entrepreneur and since then have been sent quarterly demands by unions de recouvrement des cotisations de sécurité sociale et d’allocations familiales (URSSAF) for 67 euro, as well as paying régime social des indépendants (RSI) when I complete each declaration trimestrielle. I have now received another questionnaire from CMU - Protection de base - and visited the local CPAM, where we had been before, to ask what to do with the form. The clerk did not seem to be aware of what to do and I am now in a quandary as to whether or not to complete the CMU form or what.

The Declaration Sociale section of my registration forms say that the organisme d’assurance maladie choisi is SANTEVIE prof. independantes. Who should I be paying social charges to? Why am I paying to URSSAF and RSI? Where does SANTEVIE come in? How does this affect my wife’s cover? So far neither of us have had any problems in obtaining reimbursement of doctors costs which have come from CPAM - will this change? Who do you advise I try to talk to to sort this out please? We live near Rodez in the Aveyron (12).