The school are very helpful and doing every thing they can,it may be that because her self esteem is low and her abilities also are below par she does not like it as she is unable to keep up

Well if self esteem is the problem that is what you need to work on that. Make sure you give her lots of praise when you can to make her feel valuable. Can you organise some after school tutoring to help her catch up. What does the school say about this?

Maybe she could do some outside school activity that she might be good at like sport or dancing.