What kind of software solution can we use to keep track of invoices, maintain separate corporate accounts, create work orders, etc?

We are a cellphone repair company currently providing services to a corporate clients . The problem though is we need a solution that will allow us to keep track of invoices ,maintain separate corporate accounts , create work orders with unique primary key to keep track of the different devices that we are taking in .So how we have it setup is we do pickup and dropoffs . Last is the ability to separate accounting for corporates .