Lending Club didn't respond to my emails, so I called this morning and spoke to a helpful person who said they'll send me a check. I'll go ahead and report the 1099-B on my 2020 taxes.
Before I called, I logged in and saw a January 2021 statement showing a few more dollars in recoveries, so I can expect another 1099-B for the 2021 year. (I can login and see statements and tax forms, but can't transfer money, change my address, etc.)
Background:
I had a taxable investing account, not an IRA. I sold all my notes on Folio in May 2019. A few recoveries trickled in during the next few months, and to avoid getting 1099-Bs for a few dollars in future years, in November 2019 I signed and submitted Lending Club's "Investment Account Closure Request Form - Taxable" "forfeiting all rights to all Notes, including any and all Notes in 'charge-off' status" by mailing a hard copy to their Market St address and emailing them a copy. In November 2019 I received an email confirmation from a Lending Club staffer that they had processed the form and my account was closed.
After I reported the 2019 amounts on my taxes a year ago, I thought I was done with Lending Club. I heard no more from them until a couple of weeks ago when I received the email that my 2020 tax forms were ready.
I hope my account is finally closed. Wish me luck!