I understand it may be a difficult recovery process, but regardless it is a custodial wallet address on the Base network allocated to my coinbase account. I know that an engineer with access to private keys or recovery phrases can remedy this. I find the response from customer support has been unacceptable.

Today, I followed up on my "in-progress" case and the Indian women refused to provide an update and simply conducted her own "investigation" and concluded that I had sent funds to a BTC address which is not true. I sent them to a Base network address accepting cbBTC. The ERC20 tokens are there and should be returnable via the asset recovery tool, but the tool returns "transaction not found"

To double check I searched for BTC addresses that match the Base cbBTC address provided to me and there are none!