Amount field not updated on Registration page

I have a custom radio button field which is a fee field for an event. But when the a radio button is selected by the user, the Amount field (on the Registration page under "Payment Information") is not updated. Is this a bug or is there some setting that I am missing? Thanks!

Hi Michael

I am sure that there is something wrong with your settings causing the issue. Please submit a support ticket sending us super admin account of your site so that we can check and correct it for you

Sorry for lately response. We had a holiday and I just got home, and can only reply you now

Tuan