I just ran into this in Battle Spot and I'm trying to figure out how to beat it. The answer is probably obvious but I'm new as fuck to competitive Pokemon.

It was a Gliscor with Toxic, Substitute, Protect, and Earthquake. He used substitute, then poisoned me with toxic. My attack hits his substitute which brings him back out, then next turn he uses Protect. Then goes back to Substitute the next turn, and by then he's recovered the HP he lost from substitute with Toxic Orb and either uses Toxic again (prob predicting a switch) or Earthquake and repeats the process.

The team I was running was Politoed, Toxicroak, Blastoise, but the Toxicroak died earlier in the battle. What should I have done there?