"Kelly" is a Liar & a Scammer. Anything mailed to you requiring a signature, and unable to be delivered, would be accompanied with a notice left in your box alerting you to the fact. You'd then be able to go down to the Post Office & retrieve the item.
Scammers love to use lines of BS like this. They're nothing but scare tactics. The fact of the matter is that people like "Kelly" would NEVER dare to put anything in the mail. Mail fraud carries penalties that the thought of would cause "Kelly" to wet herself. Which is why you'll also NEVER receive the notice of validation, by mail, that "Kelly" is now required to provide you with within 5 business days, as per the FDCPA.
Be Safe. Be Aware.
 Gunnar

Kelly has been calling me for days. The last message I received is the same as everyone else above. They had a parcel returned to them because of no signature...I called them and they had a lot of personal info but when she said that they don't take credit or debit cards that it has to be a check only I said ok I'll call back later and I looked up the number. So glad I did!

They have been calling me for days. Today I answered and they put me in hold to locate Kelly. Then, they told that she was busy, that she woul call me later. Supossedly, it is a document received unsigned. I do not nothing about it, I never sent such document. This is a fraud. How I report them_

A Kelly Sherman call and said they had a parcel that was unable to deliver. They sent me to a lady named Hope Angola. She said my husband owed money on a payday loan, he did not do. They hadsome of his personal  information, I told them I need to talk to my attorney and they should email me all the information they had. Of course they sent nothing. They are a fraud!!!!

Left a message and said their name was Kelly Sherman from MTS. They said they had a parcel sent to their office without signatures, and wanted me to contact them to reschedule delivery.