After you file

After filing taxes with Turbotax for 2021 I received a letter from IRS stating I owed more money due to the $1400 Recovery Rebate. I did not receive the $1400 and need advice on what should be done. I have tried to reach the IRS and after many hours on the phone have been cut-off 3 times. Still no answer as to why the Turbortax software said I owe $679 which I paid and IRS came back and said I owe $2089. Plus interest and penalties everyday.

HELP!!! I trusted Turbotax now what to do to resolve this issue.