Is it permissible to take one's right from an uncle who refuses to return inherited land by means of a trust receipt that he signs unknowingly, then take the right in cash instead of the land?

If you are unable to obtain your right, it is permissible for you to use stratagem to acquire it, provided no harm is caused and you do not exceed your due. This falls under the category of "gaining one's right," about which there is scholarly disagreement.