GFC MySQL, PHP and PayPal

I need my company's system (PHP and MySQL) to be fixed to work with PayPal's API completely. I need for the system to work completely off the IPN and do things we needed to be done before. I need the numbering system to be perfect without errors. If errors are made I need them fixed within a week. Period. When an IPN is sent, I need the script to know who to pay and how much to pay from the amount that was successfully paid. I need the system to be smart enough to know when something was paid, not paid and when someone is on a free trial. The system needs to know when to add money and not to add money. Also, you need to know how to create Excel sheets from the database. I'm not looking for new coders with no experience. I need a pro that knows how to code and when they code they know it works. You will be cleaning up old code by developers that are taking too long to finish. You may write an better code in a short period of time if you feel it's needed. This is a fix up job. Nothing needs to be created from scratch. This job requires you to be advanced in PHP, Java, HTML, CSS and knowledge and experience with PayPal and MySQL. Again, I'm not looking for beginners. Please don't waste my time if you don't know how to do these task and others. This job can turn into other jobs and possibly employment.