I never got the second stimulus payment due to closing that checking account. However, I have no way to file for the rebate to get that money in the return?

No, you should receive credit for the payment that was never received. You are entitled to it. Go back into your return and claim your Rebate Recovery Credit.

1. Log into turbo tax
2. Click on Federal Review 
3. Let's make sure you got the right stimulus amount>continue
4. Next screen asks Did you get a stimulus payment? Yes
5. Then a drop down will appear and this is where you enter your first and second round stimulus payments. If you receive the first round, you will record $1200. For the second round, you will put 0.
6. The next screen will inform you you just received a $600 credit.

Yeah,  I get how it is supposed to go. I entered the value for the first stimulus (~920 due to income in 2019) and a zero in the other box for payment 2. On the next screen it says that "We are confident you got every dollar you could based on your 2020 income of XXX" and it doesn't give me any options? It doesn't seem that my federal refund changed at all, and since TurboTax thinks I've gotten everything I am entitled to, I can't figure out how to tell it that I am still owed the second stimulus payment. 

When can I claim a stimulus credit on my taxes?

According to the IRS, you'll be able to claim a missing payment on your taxes in the coming weeks, with any payments going out after mid-February. You can start preparing your taxes now -- through its Free File tax preparation service, if you qualify to use it -- or through a tax-preparation service. The first day the IRS will begin accepting and processing individual tax returns is Feb. 12. The tax-filing deadline is April 15 this year, but you can file a tax extension if you can't make the deadline.