Just an idea, but don't call them "schemes". Scheme = plotting = evil = worried customers.
A lot of the measures will vary depending on your customer. Looking at our customer complaints for the past two years, I've realized that on the quality complaints, often the customer just wanted to "vent" about the issue and they worked through it on their own. Of course, we worked on our processes to reduce the liklihood of the problem happening again.
But on things like invoices and sales-based complaints, they wanted money back. Once that was done, they were happy.