Go straight to a professional accountant immediately!
Read the notice carefully. There is usually a deadline to protest or offer alternative information. If you missed that deadline, you may owe the funds regardless of whether the facts are right or wrong. If you got the notice “a few months ago,” it may be too late for you to appeal and you need professional assistance.
in general, if the IRS sends a notice, indicating that you failed to report income, and that you owe additional tax, it is because someone has told them that you had income. For example, if you use cash app quite a lot, those transactions may be reported to the IRS. The IRS will want to see documentation as to whether those cash app deposits are from business or personal activity. If the IRS received information about financial transactions that you did not make, you may be the victim of identity theft. It is possible that someone else used your Social Security number without your knowledge, although this might be a typo instead of intentional identity theft, either way, it’s a problem, because the IRS thinks you had income you didn’t have. The first steps would be to get an account transcript from the IRS that shows your sources of income that the IRS has on file for you. You would then reply with a letter including other documentation showing that the information is incorrect. For example, if cash app thinks you had $9000 of deposit into a checking or PayPal account, you could provide copies of your checking, and PayPal monthly statements showing that you had no such deposits, and the cash app was an error. You could also contact cash app to try to track down more information about why they told the IRS that you had this income. You might be able to find out the name or address was a mismatch.
if you can’t gather all of the facts within the time, deadline specified in the IRS letter, you at least need to send the IRS a reply before the deadline, that explains the situation, and that states that you are working to gather more documentary proof. You can’t just ignore the deadlines in the letter. For the amount of money you are talking about, and the fact that you may have let the deadline lapse, I very strongly recommend that you go immediately to a qualified, tax professional.
