TT insist that I answer questions about a business that doesn't exist. How do I get to stop?

You may have income that was not taxed. If you have a 1099-NEC or MISC that would trigger it. You must pay Medicare and Social Security Tax on income earned. The IRS collects it for SSA on Form SE for the self-employed. Your self-employment tax is calculated at 15.3% on 92.35% of your 1099 net (after any business deductions) income and also subject to income tax.

The only form that connects to the self-employment tax is the Sch C business in your personal tax return. If you have made money and not paid your FICA, like on a normal w2, you must file a business return and pay the tax.