In Coinbase’s multi-sig system, there are three keys: a user key (which I have), a shared encrypted key (which is encrypted with a password that you can access on Coinbase.com), and Coinbase’s user key. Without going into too much detail, I misplaced the shared seed password, and needed to withdraw the bitcoin with Coinbase’s user key. Coinbase had an issue with the multi-sig system at the time though that prevented it from providing its seed, so it took several months (during which the split occurred) before they sent me my BTC. However, I’m still missing my BCH (which corresponds to the same address), and need Coinbase’s seed to receive the BTC. I guess I could try to brute-force my user seed due to my password patterns, but that’s a last resort, since my BTC has already been sent.

Anyways, I recently called and got through to Coinbase, and the agent told me they will respond with more information over the next week. I’m putting any legal action on hold for the time being as a result.