You're liable for whatever tax you owe, regardless of any errors any tax return preparer made, but your tax preparer could be liable for whatever penalties and interest the IRS hits you with because of those errors.
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You have most likely received a CP2000 letter saying there was a mistake. Contact the IRS and let them know you do not agree to the new amount and have a qualified tax preparer submit an amended return with the correct information on it.
The tax professional will know whether or not you need to file an amended tax return for the State also.
You are always responsible for the work done for you by your tax preparer. That's why the IRS requires your signature on the form, under penalty of perjury. You can amend your return to correct the error. Or, you can simply review the IRS's changes, and, if you agree, sign and return the form to the IRS.
I hope this helps.
Steven A. Leahy
Please note that the above is not intended as legal advice, it is for educational purposes only. No attorney-client relationship is created or is intended to be created hereby. You should contact a local attorney to discuss and to obtain legal advice.
File an amended return by an experienced return preparer. Also file Form 843 to request the penalties be abated. You are ignoring the letters and you are loosing your rights. Soon you will be talking (if your lucky) with Automated Collections (AC) and the are called Automated for a reason. You are waiving your due process rights by ignoring the letters.