Latitude 11 5175 Can't Connect with Keyboard

I have two keyboards, a battery one and a slim one. Both of them are for venue 11 pro but they used to work well on my Latitude. They can't be connected by now. The battery one sometimes can't use the touchpad and the slim one just stop working-both keyboard and touchpad. I've connected with warranty service for a replacement for pinpoints on the bottom of the machine. After replacing, I'm facing the same problem. So what should I do? Buy a new keyboard?Please