Step 1. Go to ivet.com and click "pet parent login" Step 2: After logging in, click on "Payment Method" on the left side of the screen. Step 3: Click either add payment method if adding a new card, or click "make default" on an already existing payment option. Step 4: In the notification bar, be sure to click "yes" on the question, "Would you like to update your subscriptions to use this new payment method"