It pays to be vigilant when claiming for warranty.

Document everything like take note of the date when the problems appeared, take pictures too if you can of the damaged suspension part(s). Don't be easily swayed by the usual "wear and tear" excuse by getting a second opinion from other Toyota Dealers; at least the testimonies/observations will be from Toyota itself.

Be persistent to ask for proof on how is it possible that it is actually your fault despite following periodic maintenance. Have them explain the problem thoroughly, anything less would be subject for dispute.