Collect webhook data in chargify

Question

I have already created a webhook link like: http://ncbeta.net/proposal/hook/post_index and configured it.

I am sending an email from this function when creating a subscription. It is working fine, sends an email when creating a subscription or when click on test to simulate the hook.

But actually I need to collect all data sent to web hook by chargify. I have userd $_POST in email body. but it sends a blank email.

How can I collect this data sent by chargify to webhook? Thanks.