Updated: Feb 15, 2020
This is a very sneaky scam where the Bank Guarantee or Standby Letter of Credit Provider says they can ONLY deliver the bank guarantee on swift.net instead of swift.com. That statement alone is a huge red flag! ALL real banks and ALL real bank guarantees or stand by letters of credit are normally transmitted and delivered on the swift.com bank to bank system that is used and recognized by all rated banks worldwide or DTC or Euroclear. Any bank who says they cannot deliver on swift.com is saying i don't have access to the "real" bank guarantee and standby letter of credit delivery system, I can only use swift.net which is a completely different system by a very similar name. Swift.net DOES NOT HAVE ANYWHERE NEAR the credibility, recognition, security or acceptance of swift.com.
And the biggest secondary issue with swift.net is that messages often do not arrive directly at the destination because they have to be "downloaded" to be read. If you don't know a message is coming and you don't download it then you never know about the message and therefore its impossible for you to reply!
Many Providers use swift.net to send a worthless Bank Guarantees, Standby Letters of Credit or Blocked Funds to the client on the widely unrecognized swift.net service, then when no one at the clients receiving location acknowledges the message because they didn't know to download it, the bank guarantee provider claims they delivered the Bank Instrument as per YOUR Bank Instrument Supply Contract and YOU breached YOUR contract by NOT replying to the swift.net message so they are keeping your deposit. Its just another sad old scam to take your money repackaged in a new way.