First of all, take a deep breath and relax. You will not be arrested. Debt is a civil matter, not criminal.

Once you've done that, please read the following page regarding your rights under FDCPA:
http://www.ftc.gov/os/statutes/fdcpa/fdcpact.shtm

Said I had taken a payday loan back in 2012 and if I didn't resolve the unpaid bal he would call and speak to human resources, file felony charges against with the Sheriff's department and he would have them serve me with a warrant tomorrow Sept 09-24-13. What should I do?

He called me on my job several times and said that he was trying to collect from a loan company called Midland Bank that I had nothing to do with.  He said that I owed Midland $1500 and will settle for $200 but will need to send it to him via moneygram to close the account - give the person my debit card number and send me confirmation to my email address that the account is closed.  Mums the work ok he said to me that tipped me off that he was not legal.

Yes he called me as well! I know i made him nervous because i started asking him questions as well.  Of course you got rights to ask him questions just like he ask you stuff! And they lie about sending information and collection agency will mail you if they are legit.  Also they suppose to record you and let you know that your being recorded on the phone i notice that they dont do that either, they type while your talking this is 2013 not 1930s.

I got this call from Steven Brown Stating that I stole money and if I didn't pay a Warrant will be put out for my arrest. So I called him back to find out what the deal was he told me that I need to pay him payments. I told him I have no money to give you then he started calling my job several times a day. So today I decided to call him back to let him know that he was embarrassing me harassing me on my job.

I guess he changes his name tho . Same number same bull crap stories where does he get our info?

This guy is calling my number says hes brian an investigator I think im gonna block his number since I know hes a fake

Steven Brown came to my job posing as a harris county sheriffs dept. investigator. come to find out he is tring to collect on a debt from some agency. If he come to your job report him to the police.

A guy called me from this number stating that his name was Investigator Steven Brown and informed me that my husband had a complaint filed against him and that it would turn into a felony pending the outcome of their conversation. After I hung up and realized something was fishy about the phone call, I called back and "Steven Brown" was livid that I had called back to question him and told me that I had no right to do so. He became very disrespectful and I just hung up. I will be reporting this to authorities.

This number has been calling me at work over and over again and will not stop calling.  Saying I owe them money and asking me for my credit card information.

When this number called, did the person give his name?

Called wanted to inform me that my husband was in major trouble due to stealing money from a company and if he did not pay he would suffer the consequences. Could not tell me my husbands ssn or full name just wanted me to pay him and pay him now. Previously spoke w/ law enforcement regarding these calls and was advised to report them every time they call.  Do not send these people any money you are being scammed.

Called a friend saying I was being sued along with my friend but would not name a company or say what it was about.