I was fired , because of sleeping on post, my second write up for the 10 years I ve been with this company. My Uion is not responding to my calls.,

Although most unions and union reps are helpful, not all of them are.  When the union fails to respond in any manner at all, you should contact the union BA and president in writing instead of just leaving messages hoping that they will call you back.  There are strict deadlines for filing a union grievance and if the union misses the deadline, you are out of luck.  If the union is deliberately refusing to contact you because of some animosity they have against you, then documenting your attempts to get them to file a grievance will help you prove a possible case of the union's breach of the duty of fair representation.  This type of claim can be filed with the National Labor Relations Board. Some union contracts also allow the employee to file the first step grievance without the union.  If that applies to you, you should do so immediately.  your union contract will indicate whether you can do this on your own at least for the first step in the grievance process Having said that, it may be very hard for the union to save your job if you were caught sleeping on duty.  You should speak to an attorney to explore any other options