Build a Website - integrated to a separate logistics company.

hi, i run a repair business for small items in the medical field. the old model was that the client calls me, i organise for a courier to pickup their item, the item is received, i fix it, i manually invoice, i send the item back with a printed invoice, i chase payment. this model is outdated. i wish to get my business purely webbased. i.e. i need 1. a website to provide business information etc 2. ability for clients to create a user account 3. ability to clients enter a "job". once the job is entered, i want for the client to be able to organise their own shipping/packaging without me being contacted. i.e. a packing slip is created, printed and attached to the front of the job and the courier/freight company is notified automatically to come and pick up the job (please note, the courier company will be able to provide sufficient logistics/website for me to track the job through the business, they will also be able to provide the "code" to integrate to their business website. the company that i am looking at is [login to view URL] ) 4. once the job is received by me, i want the ability to invoice the job which can be seen and paid for through their user account on the website. 5. once paid, i can then notify the logistics company to courier the item.