the Messenger of Allah forbade Muzabanah. Ad Muzabanah is when what is art the tops of the trees is sold for a certain amount f dried dates; if there are more then I gain, and if there are less the I lose.
أَنَّ رَسُولَ اللَّهِ ﷺ نَهَى عَنِ الْمُزَابَنَةِ وَالْمُزَابَنَةُ أَنْ يُبَاعَ مَا فِي رُءُوسِ النَّخْلِ بِتَمْرٍ بِكَيْلٍ مُسَمًّى إِنْ زَادَ لِي وَإِنْ نَقَصَ فَعَلَىَّ