I changed and old 2 gang light switch with a new one like here. In the old socket there was one wire connected to the common terminal and two wires connected to the L1 terminal. When changing to the new switch I thought I moved the wires as they were from the old to new switch. But now the left switch controls the other light (up is off) and the other switch is flipped (down is off). Can anyone advise how to fix that?