MOST business that do a invoicing/customer service tracking system have it made to custom tailor as nothing out there will ever be "perfect" for what you want. You can have a generic system that you may find will work temporarily, but then you'll end up finding that it just doesn' do what you want.

Invest in the time and money to find someone who can code with MySQL and MS Access and get what you want properly. It'll cost you but well worth it in the end.