Account handed over

Went to the ER on the 20th of October, received a statement around November that my medical aid did not pay the full amount. Called them to acknowledge the debt, made a payment arrangement and gave them a date for the first installment. I made my first payment( was told that they give you 3 months to pay) not even a month after I made the first payment I receive an email that my account has been handed over for neglecting/ refusing to pay the outstanding amount. Has 3 months passed already and I was not aware? Why are we treated like flight risk ********s? Why am I not given the full 3 months to see if I won't settle the bill? If only I had a choice I would never settle for you.