Website design

Hi there techie people. I am looking for a website to be developed and I am open to suggestions on how it's gets there. What I am looking for very briefly is a website that allows people to subscribe to my service. The service will require details to be input by the customer (details of their friends and family) and they will need to be able to select some options in order for us to fulfill the service - depending on the customer this could be a lot of details so needs to be painless and as easy as possible. Irregular payments will be necessary as the service will be fulfilled on a as and when required basis, only then will a prepayment be taken with the amounts varying based on usage/quantity. Payments would need to be taken and cleared before the service can be fulfilled in time for the day it is required (at least 2-3 days before). Also I would like an email to be automatically sent to remind the customer we will be fulfilling the service and what they will be charged just before it's taken incase they want to make adjustments or skip the service. I have the idea of what I want but need someone with the know how to make it happen. I can answer questions with more details if required.