In late Q1 and early Q2 of 2019, the prices of used S9 miners went from $135 to $250 almost over night and to $325 then to $500 within the matter of literally a couple of weeks as the price of bitcoin soared. Miners became very scarce quickly. Brokers who took money from their buyers hard to option of:
1) trying to fulfill the orders for the original price
2) asking their buyers to send more money
3) waiting until the price of miners went back down and try to fill
4) refunding the buyer
Depending on what the purchase agreement / contract states, the broker might need to exchange crypto for fiat or fiat for crypto at a certain exchange rate. If the price of bitcoin is volatile, it can put the broker at a big disadvantage and quickly become an unprofitable venture.
Brokering used miners is a hard job.
Yeah even I tried to broker a few D3 and made a couple successful deals back in 2017, but how is any of what you say related to what this post is about? This post isn't about whats profitable for brokers and what's not, it's about a random dude trying to sell some miners.
So please make your stance clear on what you are here for.
As for Kaboomracks. I have never heard of em before, like I said, I've dabbled in selling mining hardware when it was profitable to do so, when it wasn't I exited. But many scammers lurked around and made the scene really shady. Every second broker was boasting for "years of experience" when none existed. I wouldn't be surprised if Kaboomracks were/are one of those types.