If you file taxes using an I-TIN and you have U.S. citizen children, you will not be able to claim the child tax credit. You will be able to use the children as a deduction, and this will reduce the total tax you have to pay.
So will I get a refund?
That depends. If your employer withheld income taxes from your paychecks, you might get a refund. You will get a refund if the amount your employer kept is more than the amount of tax you had to pay.
If your employer did not withhold income taxes (maybe you were paid cash) then you might have to pay. This depends on how much you earned.
Talk to a qualified tax-preparer if you have any questions.