Should survey for canceling subscription be before or after the subscription is canceled?

We want to collect data about why our users cancel our product subscription.

Should we put the survey form on the same page? Since it might be more likely that they will fill it in, but probably at the expense of distracting our users from their goal. Something like this:

Do you want to cancel your subscription?

Survey Form

Don't cancel my subscription | Cancel my subscription

Or let our users cancel first, then show the form in the page after that?