Is there an effective way of reporting fraud? I have the phone numbers of people running a crypto pump and dump scheme.

If I understand correctly, crypto is currently regulated by RBI in India. I checked their normal complaint portal and it didn't have a way to report fraud complaints against crypto exchanges (I didn't find it and I doubt ombudsman scheme covers it) If I understand correctly, RBI redirects reporting of such investigations to Cyber Cell or EoW of the relevant state police. You can try reaching out to them. Check this document I found on RBI's compliant portal.

Such issues also exist in penny stocks in Indian stock market as well. We cant do much in such case