transmiter-reciever matlab code simulation problem

hello everyone! i have a serious problem and your help will be very usefull to me. i made a transmiter-reciever simulation through a channel and the result is wrong.i'm searcing too hard and i cant find where is the problem.so if anyone want to help me i send him the code to check it. is really important to me cause im a student.i'll be very thankfull!!!