Have received 3 calls in 2 months. Does not leave a voice message.

have received many call. answered no one on phone

Called the number which identified themselves as Trans World Systems.  I pressed for information.  What is trans world systems?  She said, we're a global company.  A global company for what?  She just kept side stepping the question.  What number did we call?  I said, don't you know what numbers you called?  So I played back and forth with her for a while as I looked up the company.  Here's some info on them.

http://www.floridadebtfighters.com/fdcpa-righ ... sworld-systems/

https://www.consumeraffairs.com/debt/transwor ... ion-agency.html

http://transworld-systems.pissedconsumer.com/

Note that they continued to call and harass persons who proved they did not owe a debt.  Whatever you do, follow the advice of the FTC with regard to debt.  And absolutely DO NOT ACKNOWLEDGE ANY DEBT ON THE PHONE and REQUIRE WRITTEN PROOF OF DEBT.  Here's the FTC's page:
https://www.consumer.ftc.gov/articles/0149-debt-collection

Remember, debt has a statute of limitations.  So don't acknowledge debt on the phone because you will "reset the clock."  I also read on that those who work for this company are  on "commission only."  That means they don't get paid unless you pay them.  So they are going to use every trick in the book, legal or not, to get money from you.