By all means continue to ignore my requests [for 3 months] for you to come in and rectify the error you made in installation when, rather than doing it properly (and as specified), you 'bodged' it assuming that I'd never notice it because it was behind a (removable) panel.
You said you were too busy to return to do it, mentioning all the new work you're taking on. Well, you might just find that you've got more time on your hands than you thought as I've spoken to a couple of these future clients and told them what a shower of sh!te you are.