Authorize.net expert for php site

I need an [login to view URL] expert who has worked on recurring payments using Authorize.net. We have added the code to our site, and need someone to test it thoroughly and fix the bugs. Some scenarios to check.. 1. Handling cancellations of subscriptions by users 2. Handling expiration of CC or any other error during automatic payment 3. Allowing users to modify their CC details linked to their account 4. What happens when a user with subscription tries to upgrade the package