Why do you think posting your request on a website to identify unknown phone numbers will have any results? Do you think your caller watches this site and will know who you are when they see your post and will stop calling you? Just invest in a call blocker.
Scam. A real process server would never call you in advance because you could simply avoid them. And they would never give you the option of paying to get out of being served which is what these scammers will offer you. Just block and ignore their calls.
Message from a woman identifying herself as Laura (perhaps Lauren) Hoffman of the "Private Servicing Division" of some company stating that she had legal documents to serve me and would only make two attempts. Second time I've received this call in the past month.