Analyze and develop a program for Shop to Refill inks

Dear All, I have a shop to fill the inks and the sale of spare parts I want a program to manage inventory, sales, purchases, customers, suppliers and maintenance The problem we have: we are not able to manage the quantities dispensed to fill because we have multiple types of raw inks and differents cartridge types and colors and may be installation of spare parts when filling ink, so it is difficult to management when the ongoing work. This is a simple explanation of how to deal with the client: 1 - a customer brings to the shop to deliver the ink cartridges empty wish to fill. 2 - in some cases the ink can be tested and then inform the client if there was any spare parts in the other cases the ink cartridge is received then contact the customer to clarify the parts that need of ink cartridge. 3 - reported the receipt of an invoice to the client explaining the cost and quantity received. 4 - Ink Cartridge is filled from raw ink appropriate. 5 - spare parts to be installed if the ink you need to pack it 6 - The technical test packaging 7 - print bar code label contains some information like "Id customer-date-quantity Refilled" 8 - Packaging 9 - customer contact 10 - sales invoice is issued at a cost of packaging recorded in the invoice receipt. We want the link between the method of dealing with the client described earlier of receipt until the issuance of sales invoice. Regards, Coocktail