Show customers how happy you are to have them be part of your company by giving them rewards or something every so often. For example when a new customer joins Koodo you can give them a complimentary case or deduct a little amount of money off there first bill. And for already existing customers you could send them a complimentary.gift
as well only if they have paid there phone bill on time for a certain amount of consecutive months. Or you could possibly do more of those free blacks poster or something that would give them free phone cases or a free app for a limited time.