Where should I complain about the school's delay in returning my child's deposit?

[lixleon]

We are new and have lived in Singapore for less than a year.
My child is an international student who graduated from preschool two months ago.
After sending the preschool several emails asking for a deposit return, they kept saying they would return it but did not.
Does anyone know a suitable place to complain about this kind of issue?
Thank you!

[abbby]

Usually to the school first, ask them for a timeline.