Why do I get this threatening notification, 'Your account is overdue. To avoid disconnection of services, please make a payment immediately'

every time I receive an ebill from Shaw? My balance is at $0 and my bill is not due for another 3 weeks. Shaw has even gone so far as to give my phone number to a collection agency in Arizona, and they phone me to tell me that my Shaw internet service will be cut off. If Shaw wants to lose a paying customer, who pays on time, each and every time, this is a great way to do it.