Q. Why didn’t turbo tax catch this?
A. It normally will. So, I suspect there's more to your situation than just not meeting the MAGI requirement. A commom situation is that the IRS received tax documents (e.g. 1099) increasing your income. The IRS notice should also indicated anything like that.
To contact TurboTax (TT) support:
https://turbotax.intuit.com/best-tax-software/why-choose-turbotax/audit-support.jsp
