Day Trading Tax Treatment: missing 1099 from defunct exchange

I publish illustrative scenarios prepared by my practice. All participants and conversations are fictional. The fictional posts are not posts by real users, accounts of client experiences, or reports of actual results.
Illustrative scenario prepared by my practice.
For informational purposes only. This is not legal advice. Laws vary by jurisdiction. Consult a qualified attorney for advice specific to your situation.
Hypothetical question

Has anyone dealt with something like this? I'm not sure what my options are.

missing 1099 from defunct exchange. I've been dealing with this for about 2 months now and the situation isn't improving.

I have already done some research online but did not get a clear answer.

Has anyone been through something similar? What worked for you?

Illustrative response

So basically been there. Here's what I learned.

The #1 mistake I see here is filing with the appropriate government agency. I'd recommend gathering evidence first instead.

Illustrative response

Make sure you're not missing any deductions. Many people leave money on the table.

Illustrative response

Have you consulted with a CPA yet? This is complex enough to warrant professional advice.