When a child is not doing well in school, do not blame the teacher; blame yourself for not paying attention to what your child is doing, and not properly handling the information the child's teacher provides you.
Seldom, if ever, does a teacher pick on a child.
If they say your child is not paying attention in class, then you must correct him. If your child's grades are falling behind, you must be creative; take something away from the child at home until grades improve.
Step in, take control of your family, know what your children are doing and help them to learn.
Read to them when they are young, help them as they grow, be certain that they are in the right activities and enjoy the process.
Education starts in pre-kindergarten in the school system, but it starts with you parents at their birth. Do your job.