Am I being discriminated against? Internal job offer

I'm currently working as a contractor overseas and recently received an internal post of some positions at a different site. I immediately spoke to my supervisor whom is the person in charge of the section countrywide and he told me verbally there shouldn't be any problems with me attempting to join the hiring pool. However, I needed to receive permission from the overall country manager in order to even be considered for the position.

So, I submitted my paperwork through HR and checked with them for the next week staying on top of the process and they kept on telling me yes, its in the process we haven't heard anything yet. So the Monday of the next week I went in to touch base to see why it was taking so long and I got the surprise that my transfer paperwork was " lost in the works". However, the week prior when they were blowing me off it wasn't lost. This document was in fact sent by email so I don't understand how it got lost.

So, the next day I receive an email from HR stating to me that my transfer approval was DENIED therefore I would not be allowed to even be considered for the position. Due to low manpower and I'm a critical asset to the mission. However, I know of for a fact 2 people co-workers 1 male and 1 female whom are in the same skill set as me. They applied and there transfer request did in fact get approved so why didn't I ?

Do I have a case?