Claims not being reprocessed after speaking with rep

Medical biller - I am finding that BCBS IL is pretty consistently negating re-processing claims after I speak with a representative on denied claims.  I am told a claim will be sent for re-processing, that we will get more info by mail, etc... then, nothing.  I'm not sure what to do for my patients at this point.  Some of the denials are BCBS errors.  It's getting incredibly frustrating and makes my practice look bad to the patients.  What do I need to do to get action?