Have you explained how SW bill the customer in regards to metered / unmetered / assessed ?
You need to advise whether SW provide the fresh / waste or both services and if not give appropriate details.
Have you checked that the customer is a tenant or an owner?
Have you asked for the headcount in the property (add to rate data) or checked the number of bedrooms / single occ and checked against the bill created?
Have you taken a meter reading and if not, you need to explain if SW can take or would we estimate?