Interview with a Jovo

[Drich]

Refusing to hire someone who refuses to comply with their responsibilities regarding the position is not discrimination, it's common sense.

Maybe in China or the communist country where you or the OP is from.

But, here is 'Merica We have this thing call the Bill 'o rights
and it says (concerning religious freedoms

In a 1979 consultation on the issue, the United States Commission on Civil Rights defined religious discrimination in relation to the civil rights guaranteed by the Fourteenth Amendment to the United States Constitution. Whereas religious civil liberties, such as the right to hold or not to hold a religious belief, are essential for Freedom of Religion (in the United States secured by the First Amendment), religious discrimination occurs when someone is denied "the equal protection of the laws, equality of status under the law, equal treatment in the administration of justice, and equality of opportunity and access to employment, education, housing, public services and facilities, and public accommodation because of their exercise of their right to religious freedom."[1]
http://en.wikipedia.org/wiki/Religious_discrimination

Did you see that last little bit? the bit where is says"equal opportunity for employment" and "Public accommodation because of their EXERCISE of their right to Religious Freedom?" If said cleaning lady's exercise of Religious freedom has her at church on sunday then the employer must make an accommodation for her religious beliefs.

IF The OP had a business in the United States The cleaning lady who went to church could have a law suit against the OP's Company if they employed more than 15 people. but, again in the court of public opinion (as you are a member of) the OP nor his company did anything wrong. Unless she was a Jew observing a high holy day or a Buddhist doing something similar.

If they'd refused to hire her specifically because she was a woman or christian, it would be discrimination. But in this case, the reason stated was failure in meeting the  requirements. This job would mean working on Sundays and she knew that. Applying for it with that knowledge in mind and demanding special treatment is just silly.

Maybe look up the law before teaching from it next time.