MY DESKTOP IS TOO BIG !!!

I have a rpi3b+ and i bought a 2.4 inch captive screen and i installed the driver for kali linux cause its my system but when i boot the screen is too big i only see the top left part i cant see the power off button ect.. please helppp i tried editing /boot/config.txt doesnt work i tried gui version to change resolution i cant nothing seems to work