Is it discrimination if an employer requires everyone to submit to a pre-employment urinalysis drug test, yet requires a candidate of the same applicant pool to submit to a hair follicle test?

I was given an offer of employment contingent upon successfully completing all prehire screening processes. They make everyone submit to a background check and drug screen. You have to submit all the background check and drug screen within 48 hours. My background was not submitted in time. The employer said I would now have to submit to a hair follicle test to get a background check submission extension. I submitted the background check and was told that I should get a registration for a drug screen within a few business days. I received an email from HireRight with a drug screen registration and order form. That same morning I get an email from another staffing manager stating that I should email my hair test Specimen ID# to her. It never mentioned urinalysis or hair test on the registration form. I got to the testing center and was administered a urinalysis. I figured the staffing manager had just been giving me a hard time. So, I emailed the specinen ID# to the appropriate person. 10 days later, the background check states I never submitted a specimen ID# and the test was never conducted. So they sent me the wrong registration. Is it legal to disqualify me from the position based on the wrong form being sent to me in error?