Help: Light Bulb connected to two gang switch and one gang switch

[MT0001]

Hi, I am in need of assistance with reference to a wall light. Basically I have a one gang switch at first floor level and a two gang switch at 3rd floor level. The one gang switch and one of the switches at 3rd floor level are aimed to switch on and off the wall light. I have connected the COMS on both switches. The neutral has been connected, and two live wires have been connected to both switches directly from the wall lamp (L1 and L2) thus I am fiding a problem in switching on and off from the different points. The bulb switches on and off only either from one point or from the other. Is the problem coming from the COMS? Should I connect only one COM? Or is it the both switches have to be two gang? Thanks

 

[EFLImpudence]

It is not clear from your description what you have done.

Pictures of the switches wiring please.

 

[MT0001]

I will upload some pictures later, or a video if possible.