This game has no real official OST, aside 3 tracks released in a promotional album/CD.
The ones I have found online either have sfx or don't have the complete song (at least for track 11).

I looked quite carefully with the search bar and couldn't even find a mention of this game. I apologize if I missed it somewhere.

maybe this (https://www.dropbox.com/s/uq065c22j2u0ru4/Monster%20Kingdom%20Jewel%20Summoner.rar) is what you're looking for?

hey man, have you still got that soundtrack?