Auto bed leveling not registering ?

Hi,
I recently installed an auto bed leveling probe with a servo on my prusa i3. Everything works fine except that after it does the probing, it doesn't seem to register them. It prints like the probing never happened... which makes the system useless..
Have you guys encountered this problem before ?
Thanks a lot in advance

Is your G28 set for all axis? if so change it to only X and Y