Private courrior service.  Will not provide name if company when I called them back.  Only wanted my case number or phone number.  I did not give them any information.  When called the recorded message stated that I would be receiving a delivery tomorrow and I would need two forms of I'd to sign for the delivery

Scam call.  Sounds like a scam to get you to pay for a bogus debt, debt that has already been paid, or even a debt that is owed - but not to the caller.  No one gets a heads up they'll be served - ever.  Real process servers just show up, and they don't require you to have "two forms of ID" to sign for delivery.

Just got a call from these jokers same as Louise. The recorded message they left claims they are from a "Courier Service". No process server is going to warn you, common sense folks!

The number they left was for Cooper Mediation Firm. Hrmm the message said it was from a process server. Cooper claims to be collecting on a payday loan from "Castle Payday". Had my attorney call them for fun.

They kept claiming this that and the other, all bull. Attorney read them the riot act. Asked why nothing was sent in writing, all they would say is he has been contacted several times. Kept claiming I owed this debt without actually providing any evidence. When asked to fax verification, all they would say is I have been contact several times. When asked for a physical address to mail a C&D to, the guy got weird, put my attorney on hold, then hung up. Go fig!

This company is based in Western New York but is using Google Voice or MagicJack to spoof a San Antonio number.

So after I finally got a valid mailing address for these jokers, I sent a C&D by both certified and regular mail. They refused the certified but never sent the regular mail back. GUESS WHAT? They have violated the C&D. Time to file suit in court in Texas. They won't like it much, as Texas law has a nastier bite than federal law on these types of issues.

Well I hate to burst your balloon but nobody has to accept a certified letter and the fact that your regular mail was not returned won't stand up in court.  I am rooting for you on this,  however,   I have been there and done that a few years back on another issue.