I've had a seller print my full private home number on a parcel posted to me. How the heck has she found my telephone number. Ebay told me it was on an invoice from PayPal but PayPal have a different number to eBay. How has a seller found it as I can't find numbers anywhere?
Many couriers require a delivery phone number as part of their validation, so for example the driver can call you if the address is ambiguous, or there's nobody in and would you like it left or postponed...
