i would also name & shame non-payers, at least as a matter of principle, but since we are talking about big money here, the main thing is that you need to get your due payments.
So i would personally do my best to get in contact (best way face to face or at least with a phone call) with the people that owe you money, explain them what kind of problems they are causing you and, if they are not able to settle the payment pretty soon, ask for your record back and perhaps a small refund.
I actually think these people DO KNOW what kind of problems they might be causing you, but still I would suggest you spend some time to fully explain the situation they have put you in with their delayed payments...
Naming and shaming should be the very extrema ratio, because the risk is that you might not see your money before long.
And of course, no credit from now on...
best luck!