There is a procedure if you don't get a W-2 to file a "substitute" W-2. I had to do this for a client who didn't get one, didn't get one after he asked for it, reported them to the IRS, the IRS told the guy to give him one, and he still didn't get one. What you do is sign a statement that you went through all those steps, then you fill out your best estimate of the income and taxes that should have been on the W-2 you didn't get. It's always best if you get check stubs with year to date information to keep the last stub of the year to compare to the W-2. If you don't get check stubs showing your taxes, keep a copy of the checks and notate on them how many hours you worked and at what rate to get that.
If you worked 20 hours for $10 per hour and your check was $152.73, that means they withheld $47.27. Part of that will be the SS taxes and part your income tax withholding. By tracking your hours and what you got, you will have the information to create a substitute W-2 accurately. We had to do some educated guessing with my client because he had to rush that paycheck to the bank right away or it would bounce and he didn't track his hours other than knowing in general that it was usually around 20 hours a week. Not real precise ... but only the employer could dispute it and then the employer would have to produce the records of how many hours were worked.
Time to build a bigger bridge.