888-256-1994

Is it legal for someone to serve you at your work place?  I just got one from these people and I know they have my home number

So, you are now posting under different names, with a slight variation of the story.

https://800notes.com/Phone.aspx/1-714-380-5376

Depends on your state law.  Most states allow process servers to serve a party at home or work.  However, no legitimate process server
calls you up in advance and tells you they are coming by.  Also, most states require that process servers be licensed to serve process in the locality they are serving papers.  This sounds to me like some sort of debt collection scam.  And so far as I know, NO state authorizes anyone to serve process by phone.  This caller group is most likely in Southern California.  THey wouldn't be authorized
to serve process in any event,  since they are most likely not licensed.

Just because someone on the phone calling you says you owe a debt does not mean you actually owe it.

If a voice on the telephone claims you owe a debt:

1.    Demand the person give you his or her name, company name, and address
2.     Demand a debt validation letter by US mail.  E-mail no good.
3.    Do not pay  the collection agent or anyone else a  dime until the debt is validated

Of course they won’t do this, no scammer ever will, so simply ignore them and block their calls.

If they are bothering you, report them:

http://www.consumer.ftc.gov/articles/0149-debt-collection (Threatening civil proceedings with no intent to follow through, or threatening criminal process in order to collect a civil debt is a  violation of the Federal Fair Debt Collection Practices Act.)  The same goes for endless telephone harassment

Also contact your local attorney general

If they continue to bother you,  and you know you do not owe any money, tell them that you know this is  a debt scam and that you are making a complaint to the police for extortion.  Once you get a copy of the police report and they call you again , just read out the  file number and the name of the PD or Sheriff’s office involved.   Tell them you’ll be glad to send a copy to them at whatever address the jack***es are working out of now.

You'll probably have to yell at them and talk over them.
You have to get tuff with these people because,  being akin to thugs, brute force is (metaphorically speaking),  the only thing they understand.
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Note however if you are in fact served with valid service of process, make sure you answer the complaint, since failure to do
so could result in a default judgement against you.

You "just got one" what?