First of all, I am using a Sandbox account for testing.

I can successfully create a Customer Profile as well as a Payment Profile. 

The problem is that while I can add 4111 1111 1111 1111 in the payment profile, I can also add incorrect card numbers in the payment profile using my code.

I am using

1. http://developer.authorize.net/api/reference/index.html#customer-profiles-create-customer-profile
2. http://developer.authorize.net/api/reference/index.html#customer-profiles-create-customer-payment-pr...

I am expecting a function from Authorize.net which should return an error message like "Your Credit card number is incorrect."

Kindly assist me with htis issue. 

Thanks