Can an employer say I was successful gaining employment by written email then two days before the start date say the position is no longer Available?

Unless withdrwaing their offer of work violated the terms of an enforceable employment contract, then you have no claim here. Typically, just a promise of work does not impart any legal liability on an employer if it is subsequently withdrawn. That having been said, if you did not have an employment contract but you did something significant to your detriment in reliance on the promise of employment, such as turnng down another job, then you could possibly still hold them accountable for their promise. The key issue would be if this employer knew or should have known that you were quitting an existing job or that you turned down a different offer (if they knew or should have known of both, even better). The legal basis of such liability is known as "promissory estoppel" or "detrimental reliance". To prove such a claim is must be shown that there was 1) a promise which was reasonable to rely on; 2) reasonable reliance was in fat put on that promise; 3) in reasonable reliance, you changed your position to your detriment; and 4) this employer knew or should have known at the time they made the promise that it would be reasonable for you to change your position in reliance on the promise to your detriment. At this point, you can consult directly with a local employment law attorney who can best advise you further on the matter.

Unless you had an actual written employment contract for a defined period of time (e.g. a one-year contact) guarantying you the job, this is perfectly legal. Without a contract, employment is employment at will: the employer is 100% free to refuse to hire you, to hire you then change its mind or withdraw the offer or cancel the position, or to hire you then promptly terminate you. An employee at will (someone without a contract) has no right in or to a job.