Believe it or not some customers even reach out, and say that they want a return, a refund. And that they will ship back whatever remaining products they have..
It doesn't work like that.
That's like ordering a platter from a restaurant, eating half of it, then telling the service that the food was disgusting and you're not paying for it, or you want a refund.. lol
The loss of a few vials is petty, and everything is negotiable, whether or not the negotiation is easy is another story.
And on the flip side, sometimes customers try to hold sources hostage, by blackmail or extortion with threats to go open to the communities if they don't abide by their demands and ultimatums.
I seen customers do some fucked up shit, and go to great extremes and measures, a famous one is when from the very beginning they stomped their feet and say "I will take this to the forums and social media, and I have a lot of followers, I will tell everyone my experience, I'm a pro, I should be huge by now, unless"..
Nothing is more comical than the idea of giving a customer more of the same product that they emailed about pissing and moaning about how bad it was, and they want a replacement of the same product for free!
The consumers rights act from 2015 with a 30-day window returned, money back guarantee with most services does not apply in the black market.
But here particular, the customer and the source both did the right thing. Situational awareness, and damage control and making it right.