I had a client who was consistently late every month by a week or two and I needed to put a stop to it. So I wrote in a new policy that if payment wasn't made within 5 days of the due date a 25% late fee would be imposed on the account. They paid the late fee one month, then after that made the payment before that. They still don't pay on the due date, but at least I am not waiting for two weeks every month for the payment.
I also stipulated that if the account is over due it can be suspended and access to our servers blocked until payment is made. Although I didn't suspend the account, I would suspend an account if a customer was consistently late and didn't make it a point to talk to us.
The new policy is only seen by clients who pay late. I write it into the email that sends out over due notices. This way, only the people who are late will be affected by it and not the people who pay on time.
Some of this was a juggling act because I thought, do I send an email to all clients about this? Then I thought, being that I pay my own provider on time every month, if I got a notice like that I'd be offended and would not think well of them. If I got a notice like that because I deserved it, then I have no reason to be offended. So I wrote in the new policy so that only people who are late payers will see it.
I'm also working on a points system. Both positive and negative. For people who are late payers, each month they will receive a certain number of negative points. I have to work out yet how they will be affected by accumulating a certain number of points. For the people who pay on time each month they will receive a certain number of positive points and will receive a reward. That could be most anything, possibly one month free every two years. Maybe an extra addon for one month, or something of that nature. I don't have it down yet, but am working on some of those ideas.
You take for example stores that distribute a card to their customers and when they shop there by using the card they receive a discounted price on marked products. It's a game actually because I know of one store here that uses it and they are actually high priced and I don't shop there. I shop at a different store where I don't receive discounts but the prices are still lower than the other store. But most people don't think that way. So if I implement both worlds into my business, competitive prices and incentives, that not only brings customers, it will help keep them.
Just a few ideas.