Here is the actual data (just a few years old though)
If you make only 30K (in pre-tax income) a year, that places you roughly in between the bottom two income quintiles.
You can clearly look that the bottom 40 percent pay no income tax as the numbers for the bottom two quintiles are negative for their share of tax liabilities. This means your refund at the end of the tax year more than offsets the federal income taxes you had to pay over the year. That said, you are correct about having to pay other taxes, but in terms of the federal dollars (since that's the focus, and some states have no income taxes and others have low sales taxes), there is no national sales tax - just excise taxes and safety net taxes.
Based on the numbers you cite above and the data provided by the CBO, your numbers don't match up. Your 2K seems to be in the Social Insurance & Excise taxes part, not Income tax. And in the offshoot chance that I'm wrong, I'd recommend getting a new tax accountant.