Crystallized THCA. See: D8 thca
D8 THC
Heat THCA, and it decarboxylates, physically loosing CO2 to become THC.
Yep, there are some folks around here who can put that genie back in the bottle. You can read of it here.
But if you’ve not got enough chemistry to tell THCa from THC, you’re not gonna get where you want to be.
What is wrong with what you purchased?