Billing system bugs to be fixed

I have a billing system that bills my clinets on the same day every month and also talks to our accounts package via xml I am looking for someone that can look through my entire billing system and make sure all the bugs are fixed a certain things in the system dont seem to be working correctly. For example when trying to add a new product i get error with database. when i do a import i get certain errors. there are duplicated items. Items show that should only show ocnce and not every month when billed. there are a number of small issues due to bugs in the system. The system is built its just certain things dont work correctly ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform php mysql