ACS, INC. harrassing phone calls and emails threatening legal action Internet

I have been recieving threatening calls on my cell phone, work phone, and now via email saying that I have a payday loan that I did not pay.  I started to apply on line for a payday loan about a year ago but did not follow through.  Obviously these people were able to get my information.  They leave threats, say that I need an attorney, etc...   They then say that I owe thousands of dollars but if I will pay them over the phone right then they can take a settlement of only hundreds of dollars instead of the thousands.  They leave different names, speak in an indian accent.  I am not sure if the ones calling on the phone are the same scammers that are now emailing me.  I hope someone can stop these people because it is very stressful and I am sure many people have fallen for this and paid them.  Make them go away!