Is 309 the tax due on your tax return line 37? You do owe that when you filed. Did you have self employment income? You might still owe self employment tax on that.
The self employment tax deferral was an optional benefit. It is also a deferral rather than forgiveness, so those amounts will eventually need to be repaid. Half of the deferred amount is due on December 31, 2021, and the other half is due on December 31, 2022.
Check if you have a Schedule 3 line 12e which goes to 1040 line 31.
How to pay the deferred self employment tax
https://www.irs.gov/newsroom/how-self-employed-individuals-and-household-employers-repay-deferred-so...
