"through bullying that they received" sounds a bit weird, because bullying is not so much something you receive as it is something that is done to you. And also you can't have "regarding with," it is just "regarding." (received regarding their non- branded clothing) Perhaps "This contributes to the marginalization of students who were bullied due to their non- branded clothing" sounds better.

I would say: This contributes to the marginalization of students by the bullying they received because of their non- branded clothing.