Your problems are with the IRS, not the INS. Even there, the penalty is only 10% annual interest , if any tax is still unpaid. Send whatever documentation you have. Tax returns, transcripts, W-2's. If you wish, you may document the missing W-2's. Write a letter including the company name, amount earned, and that the W-2 was not received. If you use only the mother's income, the father's need not be documented. The consulate will want to verify only the income, not the tax return itself.