Dentists wont fix my teeth?!?

Why won't a dentist help me out. I have insurance and chipped my tooth (I'm a night grinder). Got a night guard, which isn't correcting the chips and the teeth after the grinding and other forces have shifted the teeth after braces removal almost a decade ago. Called former orthodontist, won't return my calls. Dentist says "Can't bond them because you'll just knock that off". My teeth aren't THAT crooked, just a little chipped and shifted. I don't want braces again. A cosmetic dentist said they don't treat "problematic unhealthy teeth" (which isn't me!). Why won't they help me out?