Special kind of dual switch?

[NYC handyman]

Hello!
I replaced a bathroom dual switch (a piece of plastic had broken inside the top switch) with a Decora 15-amp single pole dual switch from Home Depot.
Originally, the top switch controlled the ceiling light, and the bottom switch was for the vanity lights around the medicine chest.
I wired the new switch EXACTLY as the old one.
Now, one switch controls both lights and the other does nothing.
Is there some sort of special dual switch that I need to buy?!?
Thanks for any guidance.

 

[Electro-tech]

I take it you are safely isolating the power? Do you have an electrical Tester? Post a picture of the back view of the switches & wiring.

 

[timhoward]

Yes, photos needed. Turn power off first.

 

[DPG]

Yes, photos needed. Turn power off first.

I see you changed your emoji after the other thread then

 

[Lister1987]

Hello!
I replaced a bathroom dual switch (a piece of plastic had broken inside the top switch) with a Decora 15-amp single pole dual switch from Home Depot.
Originally, the top switch controlled the ceiling light, and the bottom switch was for the vanity lights around the medicine chest.
I wired the new switch EXACTLY as the old one.
Now, one switch controls both lights and the other does nothing.
Is there some sort of special dual switch that I need to buy?!?
Thanks for any guidance.

My money is an incorrect strapper; If inserted into the wrong section it will effectively by-pass the switch.

 

[Lucien Nunes]

Note that the OP is in the USA where dual-gang i.e. duplex switches often have a snap-out tab linking the two common terminals (which are also usually identified by being bronze or black.) If the terminals of the new switch are on the opposite sides of the body to the orignal but he matches the original wire positions instead of the screw colours, he will have the incoming hot wired to one switch, the ceiling and vanity cabinet lights both wired to the linked commons, and nothing to the other switch. This will give exactly the symptoms he describes. There are other possible explanations of course.

As above, pics needed.