Recently, I've been going through some threads and seeing the seller posting "If I do not apply the pin myself, then I am not responsible for it". Disclaimers like these are not allowed: regardless of how you obtain your pins, you (the seller) are responsible if they do not work. If you do not trust the buyer to state whether the pin actually works, use an MM.

If the buyer is claiming that the pin DOES NOT WORK, adequate proof must be provided to the seller (not a picture that says "invalid pin"). If the seller refuses to provide another pin you may post your evidence in the report a scammer section.

To avoid all confusions,

1. Use a middleman
2. Use Teamviewer to apply the pin
3. Apply the pin yourself