Only use Flexepin on secure payment pages, as per Rule 3. It is never acceptable to share the 16-digit PIN in the following ways with another person: verbally, by phone, email, scans, or other web-based messaging systems.
Even when dealing with the Flexepin team, do NOT disclose your 16-digit PIN, only disclose the serial number. Any request to disclose your 16-digit PIN or any part thereof is indicative of a fraud or scam.