You'll be fine.

I think you'll be fine. First, tax documents are not required for I-140 and I-485. Their porpuse is to show your income. Second, paying social security tax is part of your benefit, since your employer has to match up the same amount you should pay and you can get social security benefits after you are 62.Your employ didn't deduct this tax from your paychecks and this means they didn't match up. Your employ is saving money from you and it's totally their fault!