So I ordered 200mg of #4 heroin from a vendor. I weighed the product and noticed it was underweight by about 40mgs. Which was no big deal to me. I politely told the vendor and their response was "I use a pretty precise scale." Was kind of bummed out that I had been shorted considering I only bought 200mg.
Just post a negative review on reddit and leave negative feedback. That's all you can do