While I love Mackie as a company and I am a big fan/owner of some of their gear, I have to say that their repair strategy isn’t the world’s best.
Getting replacement parts IS a bit of a challenge with them.
You did fail to give us some more info on what exactly “blown” up means.
– No more sound (amp shot?)
– Sound but distorted (amp, low end or high end driver?)
– Sound but additional noise not being distortion (buzz, humm, crackle?)
I also agree (with the price of the Thumps and based on their actual age) that looking out for a used one to strip for parts (if it looks worse or is older than your own) or replace the blown one makes good sense.