Your W-2 forms should be mailed out to you, or hand-given to you, no later than January 31st. If you haven't gotten your form before like Mid-February, then ask your employer about that. If your employer refuses to send it back out to you, then you can get in contact with the IRS. Your employer still has time to give them to you, so don't worry if you haven't received it yet.
Jan 31st is the deadline to either mail it or give it to you personally if you are still employed by them. I doubt someone would REFUSE to mail it out again, but they may charge you to get a duplicate copy if the address they had on you was not your current mailing address and they have not received it back in the mail yet. So you may want to contact them and ask if you can pick it up if it gas not been mailed yet.