You cannot compel the employer to reveal this information now.
But you have a right to know the allegations and to be able to answer to them.
If it turns out you are not able to answer them because they won't give enough facts and then you are dismissed for cause this could be a case of wrongful dismissal.
And if you end up in Court at that point they would need to reveal all the information including the name of the complainant.
I am sorry this happened to you.