RFA 2012- Correct Billing

We are an Ambulatory Surgery Center

We have always in the past used ICD9 code 04.20 for an RFA procedure. We recently received a denial (our first denial) for an RFA done with the new 2012 CPT® codes 64635, and 64636 (These codes replaced 64622, and 64623). We received a denial stating that "A professional review has been conducted and a denial made- icode 04.2 / CPT® 64635 & 64636 does not cross code to this code, please resubmit with correct icode". Ive researched and researched and to my knowledge we have billed correctly with updated codes and the ICD9 code has not changed. Also just for additional information it was a left side lumbar RFA, we billed 64635 & 64636 at 1 unit each, with a diagnosis of 721.3- Facet Mediated Lumbosacral spondylosis.

HELP PLEASE!

re: RFA 2012- Correct Billing

The ICD-9-CM Procedural code is 03.96