Pipe cleaners work very well too.
You should have bought my Shocker 4K, I'd have packed it right. I've had amps dropped and broke worse. You really have to pack these things to survive a 2 story drop because that's what UPS does to them. If it wasn't double boxed with plenty of padding UPS will not honor an insurance claim, FedEx and USPS are a little better.
I had a Fusion 4K dropped so hard it broke off the power terminals from the board and a Zed Milith (last gen mono amp) where someone drove a fork truck into the side of the box and put a 5" fork blade divot in the heatsink.
Street guys do.
Someone packed it improperly, very probably insurance won't pay, and the seller is going to take it up the arse if you make a stink about this most likely. It's rough because when you blow it up you'll always wonder if it was some damage done by the drop.