Check the stitching on the side panels before you buy, that's usually the weak spot.

Read an article once that called this the "zombie client" problem. They come back to life after you've written them off. In my experience, you have to decide if their money is worth the bad manners. I'd probably reply but update the quote with a small "reactivation fee" or just a higher rate. It sets a boundary that your time isn't something they can just pause and restart. Lets them know their ghosting has a cost.

Depends on who's reading it. Are you sending these to your boss or just keeping them for yourself?