case number using passport number & time between petition to stamping

My petition is got approved after RFE. but my company is keeping case number\ receipt number secrate.

  1. is there any way to get to know case number\ receipt number using passport number.?

  2. till what time my petition will be valid to go for stamping (maximum time delay permissible
    between petition approval to stamping)?

  1. NO other way AFAIK, Ur Employer must know it. However they must provide i797 when U go for stamping

  2. U can go for anytime to stamping before ur validity, however U must specify the reasons for delay