This answer should help if your switch was correctly wired in the first place. First of all, identify the two main cables that bring those 5 wires into the switch backbox. For the purpose of this description we will ignore the two earth cables (the bare copper wires that will also be amongst your coloured wires) They should be connected to the metal back box behind the switch and also have a green and yellow sleeve over them.
Also note the switch will have three terminals marked COM, L1 and L2. Out of the two main cables coming into the metal box, one will have two coloured wires plus the earth wire and the other will have three coloured wires plus the earth. Starting with the one that has only one red and one black, connect the red to L1 and the Black to L2.
This will leave the cable that has the Red, Blue and Yellow wires. You will then need to look at the other switch that controls the same light - unscrew this other switch and note which colour wire is connected to which terminal. Then go back to the original switch and copy the pattern exactly. (for example if the blue wire is connected to COM on the second switch then connect it to COM on this switch) It doesn't matter which colour is connected to which terminal, as long as it matches the second switch. You will then have L1 and L2 with two wires each and COM with only 1 wire.
Make sure your connections are tight, put the power back on and test to see if both switches control the light properly.
Rupert, December 2019
