The critical information in your question is in the last sentence--that you turned down three other jobs. Ordinarily, in the absence of an actual employment contract, an employer is free to change it's mind about who gets a job, to go back on its promises, etc. However, if they represented, or stated/promised, to you that you'd get the job; it was reasonable to rely on that representation (so no reason to doubt it); in reasonable reliance on that representation, you did something to your detriment (like give up other job opportunities); and the employer either knew or at least should have known you would do something like that (e.g. they knew you were actively looking for jobs, and it would be reasonable you'd call off your search when you had one); then those factors may make the promise enforceable. From what you write, it would be worthwhile to consult in detail with an employment law attorney, to see whether you do have a case, how strong it might be, what it might be worth, and what it might cost to pursue. Good luck.