Dr. Ramin Homanfar DDS Paid dentist 1,200.00 for my part of dental work, and 9 months later they called me about an unpaid bill I never knew about Reno, Nevada

In October of 2008, I went to Dr. Homanfars' office for dental work. They told me my part of the bill was 1,200.00 which I paid in full. He completed the work, and after the work, I had severe pain for a week. He ended up redoing all the fillings he put in and told me no charge.
Nine months later his office called me informing me that I owed them 867.60 and I asked her for what and to please send me a statement. She informed me that they do not send out statements, so of course I wouldn't know I owed money. I still insisted on a statement. She agreed to send one. I never received that promised statement. They called again 2 months later and told me I still owed them money and that the dentist ate about 600.00 that they wrote off and that my share was still 867.60. I again asked for a statement so I could see the charges. I don't know anybody who would pay that amount without knowing for what.

Three days later (October 13, 2009) I receive a letter from them saying...
"As you know your account is 90 days past due. At this time your account balance is 867.60 and is due. The last payment of 1,200.00 was received on September 30, 2008.
For one reason or another, you have been unwilling to proceed with payment. Therefore, we have no other choice but to begin a more aggressive action.
Please pay your balance now so that we can avoid any further actions---which will be unpleasant for both of us.

Sincerely,
Ramin Homanfar, DDS  "