Unfair suspension

I was recently suspended by a manger from other department @ work Jst because he didn't like they way I answered to him bear in mind he is not my manager, this guy humiliated me in froint of the staff assolted me and told me to go. When I asked how can u suspend me with following the proper procedure like a wretten warning first, confirming with my manager... When I went to HR they couldn't be with assistance worse thing this manager tells me whn I come to a hearing on Thursday I can not bring my own person to represent me there, which got me thinking are these manager miss using there position to do what they want without following proper procedures? What is the use of them to have an HR department? If they tell you that they will not hear my side of the story. This is unfair and against labour laws in this country