spells – How would a Warlock use/cast Healing Elixir?

I play a Celestial Warlock in a campaign we just started, who took Healing Elixir as one of his first spells to support our party. I plan to expand into Divine Soul Sorcerer later. My build would be 14-ish levels in Warlock and the rest in Sorcerer.

So we participated in our first major battle against a bandit raid while we protected a caravan, after which I tried to cast Healing Elixir. My GM asked me if I have any Alchemist’s Supplies on me, to which I reply “no,” but I have my focus which replaces any material components that spells don’t specify with a gold cost.

His rebuttal is that since Alchemist’s Supplies themselves have a cost, I still need to have them, but the spell doesn’t state their cost in the spell description.

I’m kind of at a loss about how I should respond to this or whether I am behaving overly concerned.

We are only a level 2 party verging on level 3 now, so should I just scrap it entirely?