Mr. Davidson and Ms. Dommershausen give you good advice. An employer does not ordinarily need a good reason to fire you. In any event, if the company has already hired someone who "is doing my job" and "has taken my responsibilities," then not only can the company fire you, but it seems like the handwriting is on the wall.
Your protections are few, in the absence of violation of a written employment agreement or unlawful discrimination or retaliation.
I suggest you start a job search at your earliest opportunity.
Good luck to you.
Michael S. Haber is a New York attorney. As such, his responses to posted inquiries, such as the one above, are limited to his understanding of law in the jurisdiction in which he practices and not to any other jurisdiction. In addition, no response to any posted inquiry should be deemed to constitute legal advice, nor to constitute the existence of an attorney/client or other contractual or fiduciary relationship, inasmuch as rendering legal advice involves the ability of the attorney to ask appropriate questions of the person seeking such advice and to thus gather appropriate information. In addition, an attorney/client relationship is formed only by specific agreement. The purpose of this answer is to provide the questioner with general information, not to outline specific legal rights and remedies.
You haven't provided a lot of information regarding your position, however, assuming you are employed "at will," yes, they can hire someone else and let you go. They can eliminate your position altogether and let you go. They can close the entire office, and let you go.
If you are a contract employee, then look at your contract. If you are a union employee, then go to the folks to whom you pay union dues to protect your job against the caprices of capitalism.
Please note that this answer is generic in nature and does not constitute legal advice with regard to any particular circumstances or facts and does not establish an attorney client relationship.
Unless you have a contract, they can fire you. Yes, it is likely that you would be able to collect unemployment.
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