These kind of concerns are why I either buy through a dealer or through a company when used… like Echo, or Upscale. My audio equipment is the second largest investment I have after my house. Buying used makes sense, but worrying about shipping, and perhaps a seller that is less than perfect is just not worth the stress.
Choosing the right audio component has lots of uncertainty and requires a great deal of effort. Throw on top of that, uncertainty about the seller, shipping, all possible ways you can get taken advantage of… not worth it to me. What are you going to save?
I buy from dealers and companies that take the worry about shipping and condition of a component out of the equation. I can sleep at night. I know I am going to get what I paid for.
Perhaps it was buying my first car (used) in Chicago, from a completely dishonest jerk. I completely got taken. I ended up paying more for the repairs than the initial cost of the vehicle. I don’t like worrying any more. Seeking a “great deal” can have costs.