If this was a rating battle, then all Pokemon are set to level 50, which means that Togekiss' Max Speed is 145.
Even though your Froslass' Speed is not as good as it could be, it is still enough to outspeed Togekiss.
There are still many ways for Togekiss to out speed your Froslass though, there was probably something you missed during battle.
Here are some possibilities:
- Togekiss was holding a Choice Scarf, which boosts Speed, and locks the user in to a move.
- Togekiss had a Speed boost or Froslass had a Speed decrease
- Sticky Web was on the field
- Your Froslass was holding a Lagging Tail
- Togekiss was holding a Quick Claw
- Togekiss used a priority move
- Froslass was paralyzed
- Your Froslass doesn't actually have 165 Speed
Out of all of these, I find it most likely that Togekiss was holding a Choice Scarf, as it can be missed easily if you aren't looking for it. Something that hints a Pokemon is choiced is if they continuously use the same move for the duration of their time on the field, switching allows them to change moves though.