TeacherActive interview questions

I received a call following an online application which was somewhat of an informal interview (telephone screening). I was then selected for a 2nd interview with a senior consultant. I received extremely positive feedback and was then selected for a 3rd interview with the branch manager. I waited for nearly 3 weeks for an update and have only received feedback now to say I was not suitable for the role with no constructive feedback or a valid reason why I am not suitable.