What is a legal view of how to defend my self?

i am being accused of cutting a bus seat (i DIDN'T). well what happened was i was siting drivers side 3rd seat from the back playing nintendo on my way home. and the bus driver accused me of cutting the seat on penger side in the back.??? for weeks i been doing after school service. my school is all white with 8 Hispanics 3 islanders 4 blacks. if it would help. i just need legal advice to get out of false accusations of me.