I have finished watching the anime but i wan to read the manga, can someone tell me where should i start reading? Which chapter or volume. Your help is very much appreciated!

The whole thing the anime is really not up to par with the manga

Think it's around volume 13 or 14 but basically everything in the anime branches of when they reach the location of the shaman fight.

So where do you advice to start reading? Volume 13 or 14?

Start reading 13, and skip chapters till you come to the point where the anime ended. Though I'd recommend reading from the beginning, as manga-anime stories tend to differ.

There are times when you will miss what you never had. I wonder how you will find what you so desperately need.