You will have to print, sign, date and mail your 2020 tax return to the IRS since someone else filed before you claiming you as a dependent. On your return if you are not eligible to be claimed as a dependent then do not indicate you are a dependent. Mail your tax return. If you are owed a federal tax refund the IRS will pay the refund.
See this TurboTax support FAQ for how to print a tax return for mailing using the online editions - - https://ttlc.intuit.com/community/printing/help/how-do-i-print-and-mail-my-return-in-turbotax-online...
Within a year the IRS will contact both you and the other party by mail to investigate the dependent issue. The loser of the investigation has to repay the refund and pay interest and possibly penalties.
