If the Investigating Officer (IO) has mistakenly included incorrect facts in an FIR registered under Section 156(3) CrPC, the complainant has several options. You can approach the IO directly to correct the details or wait for the Final Report (FR) to be submitted. It's advisable to consult with an advocate to obtain the charge sheet or FR and plan your next steps. During the trial, you will have the opportunity to refute any inaccuracies.