hi, this is quite worrying!!!
You need to understand the basics of electrics to do even such a small job as changing a switch since getting it wrong could easily kill you!!
If you have three wires which are all reds then they are all LIVES of some sort!
Neutrals are rarely found at switches and will be black/blue & in a connector not part of switch, earths are always green/yellow.
Do you mean all 3 are in one terminal or are they 1 each in 3 terminals?
if the latter then you have a 2way switch & you need to note which red is in the term marked C (common) and fit a new 2 way switch like for like.
If you mean all 3 are in one term what other cores do you have?
more info please