Turning On "Negative Testing" for Sandbox paypal (NVP/SOAP API)

Question

I want to turn on "Negative Testing" for sandbox paypal testing. As currently paypal purchases becomes successfull even if there is zero balance in Paypal, it automatically deducts it from credit Union card.

But I can't find the option to turn ON "Negative testing" in my Profile tab of sandbox facilitator account as described here.

screenshot of my profile page

Answer 1

I found this option here: https://developer.paypal.com/developer/accounts/

1. Click on arrow close to the email address of the business account (to show the links)
2. Click on the profile link
3. Go to settings tab
4. You should be able to set Negative Testing to ON

Screenshots:
Profile link: https://i.sstatic.net/6krFz.jpg
Negative Testing option: https://i.sstatic.net/KDf1P.jpg