got 400 law tomes where do i trade them esos?

[ExKage]

It's also always been the same NPC every time we get a tomestone tier taken away.

The same place it's been since we were trading philosophy for mythology...

To be fair, OP's account is from June 2015 so it's possible they weren't around for the tomestone tier taken away and having an exchange.
Edit: Yeah I looked at their lodestone, their first achievements were June 2015. http://na.finalfantasyxiv.com/lodest...t/37d5a29a600/ The Gridanian Envoy achievement earned on 6/24/2015. OP hasn't ever experienced the tome exchange.