Client breaks contact and mangles website I use in my portfolio. I thought I’d link to my staging site instead – Should I add a note explaining this is a demo only or say nothing? If so, what should I say?

I'm struggling to come up with a note on the staging site that adequately explains the situation, without making the client look bad. Would appreciate any advice on wording this. Or am I overthinking and should just keep it simple like – "Please note this is a demo site".