Your tax "return" which is actually a refund depends largely on how much you overpaid throughout the year. There are lots of factors that ultimately determine what your taxes are. Other than your income, you didn't give us any of those factors. The big problem with Turbo Tax is that many of the people preparing their own returns, don't know how to do it. Turbo Tax is now offering people the opportunity to show their tax returns to tax preparation experts and have them review them and look them over. Did you use that service?
But no, you can't sue Turbo Tax. You have to review the terms of their guarantee and what your remedies are.
This question cannot be answered without a little background. Before you even get there, your questions states that Turbo Tax promised to give you 100% of your tax return and, apparently, that's what you got. Are you saying that Turbo Tax promised to get you the Maximum return as opposed to giving you the total return amount?
Your question also fails to give any details of what went into the return and who prepared or reviewed the return.
So, if you want some advice about this issue you have to give a little more background.
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