844-886-7142

Received a call and answered it but put mute on.  The line was disconnected after 10 seconds.

Calls often, debt collector MCB management or something, left voicemail once.

They call all the time with the same recording debt collector and to call a number if it is not you.

Received another call at my work after I told the person to not contact me at work since this is a personal matter.  Plus the fact I have not even received anything in the mail from this company

They are not required to send anything out until after they have made first contact.  It would have been better if the law had been written the other way around, but we have to live with what it says.  You will need to follow that verbal request up with a letter on a company letterhead stating that you are not allowed to receive personal calls at work.  It should be sent certified, return receipt so that you can prove they received it.

It is incumbent upon them under the law to prove that the debt exists and that you owe it, and (this is the important part) that they have the legal right to collect it.  You are not obligated under the law to prove that you don’t owe or that it is paid.  

Federal law (FDCPA) requires them to send you a letter (US MAIL ONLY) postmarked within 5 days of their first contact that contains their name, physical address, the creditor’s name, and the amount of the alleged debt. It also must contains “mini-Miranda” telling you that it is an attempt to collect a debt and that all information will be used for those purposes.  The one other important thing that this letter must also have in it is that you have a right to dispute the debt within 30 days of receipt of the letter and if you do so, all collection activity must be stopped until the debt is verified.

First, you should make a complaint at this Federal Agency, and while there you should also read up on how debt collection is supposed to work as well as what your rights in this matter are: https://www.consumerfinance.gov/

Also file a complaint with your State Attorney General's office.
List of State AG’s offices:   https://800notes.com/faq/attorney-general

I've received multiple calls from these idiots and they never leave a message.  Will be blocking the number from now on.

Scum bucket company trying to collect on a bill that was closed years ago.  I've told them that multiple times and to check with the company to verify.  They don't and a day or two later another loser calls from the SAME phone number starting the collection process all over again.