Oh man, that sounds bad. I didn't go the crate route of course, so have no direct input on how to go about it. I know it can pay very well. But not familiar with the mechanics.

Look back a few posts and find the instructions I wrote for creating a solo lobby and you won't have to deal with the people that want to blow your stuff up.

You might be able to gain some insight and a few tips from this reddit

https://www.reddit.com/r/gtaonline/comments/5ucgj5/are_the_crates_doable_solo/

Or this

Lone Wolf Crate Guide


Animals flee this hell, the hardest stones cannot bear it for long. Only men endure