2) The transfer needs to be handled by myself or a formal agency at the Patent Office.
3) Generally, the transfer needs to be confirmed by yourself and a third party, or someone else entrusts an agency to talk with you, which is credible.
4) These companies lied about how much you need to pay first to negotiate successfully for you. Its company must exist.
Only after the transfer is successful, the buyer will buy the patent from you, and the intermediary will charge the commission, not before the transfer.
5) These companies are deceptive. Can be ignored. Ignore them.