This is the TurboTax user community forum. We cannot answer any type of questions concerning your Credit Karma bank account or other type of personal banking issues.
Go to this website for Credit Karma support - https://support.creditkarma.com/s/article/Contact-us-US?categfilter=About_Credit_Karma_US&childcateg...
If the federal tax refund was sent to a closed account, the bank would be required to send that refund back to the IRS. The IRS will then mail the tax refund as a check to the address you entered on your tax return.
If you no longer live at the address you entered on the tax return, the check is sent back to the IRS.
You will need to contact the IRS concerning a lost refund check. Go to this IRS website for information on how to report a lost check - https://www.irs.gov/faqs/irs-procedures/refund-inquiries/refund-inquiries-0
