I recently started working at a company and submitted a fake experience letter. Unfortunately, they found out and let me go immediately, holding back my pay. What legal options do I have now?

You have very limited legal options. Submitting a fake document is a serious offense and your employer has grounds to terminate you without notice. You may have a claim for unpaid wages, but only if you worked during your employment period. It’s advisable to consult with a lawyer to evaluate your specific situation.