Okay, so replace toxic spikes with gyro ball, yes?
SDef could save him from neutral special attacks, but yeah, of its ice beam or light cannon or such there's no chance...
Not just that. Replace one of your other hazards with Earthquake or Volt Switch.
And it's "Flash Cannon", not "Light Cannon".
@Krystia: not all slow teams need Trick Room. The team has to be built around the move (which this team doesn't look like it is), instead of the move being slapped on the team with little to no thought at all.
Edit: here's a standalone Trick Room setter in Reuniclus. It helps vs. offensive teams:
-Trick Room
-Psychic/Psyshock
-Shadow Ball
-Hidden Power (Fire)/Focus Blast
Nature: Quiet
EVs: 192 HP/64 Def/252 SAtk
Item: Life Orb/Leftovers
Ability: Magic Guard
Porygon2 can also act as backup, but find someone else to take out:
-Trick Room
-Ice Beam
-Thunderbolt
-Recover/Tri Attack
Nature: Quiet
EVs: 252 HP/252 SAtk/4 SDef
Item: Eviolite
Ability: Download/Trace