Hi we bought some new light switches for our house, we have stair lights and a switch that controls them downstairs and upstairs, with the old switches you could turn them on downstairs then turn them off upstairs then back on upstairs etc etc since putting the new ones in you can only use one at a time so say you turn the lights on downstairs you can turn it off upstairs but have to turn them back on downstairs and vice versa, it's the same with both our passage lights except we only changed one switch on them so far? Hope this makes sense and someone could shed some light on the situation. Thanks.

You either have the wrong switches or rewired incorrectly. Do any of the switches say ON or OFF? There are a couple of ways to wire 3 way switches depending on whether the power comes through the switch or to the switch. Get back to us about the switches and the wire colors on the switch.