PIN

Somebody sent me a message to my PIN but they are not one of contacts. I don't know who it is. I sent them a request and replied to the messages but they are not responding or reading the messages. How did someone get my PIN and send me a message without me authorizing them as a contact? Is there any place to go to search this PIN and see who this is? My ex husband is already hacking into my computer, I don't need him in my phone as well.

Debbie

I never posted it anywhere. I only have given to friends and family. I only have 11 contacts. This is a new account that I opened a year after the divorce and I had moved to another state and changed carriers and phone numbers. I know the number is a Verizon PIN because all of my contacts who have Verizon. I also spoke with AT&T and they confirmed that Verizon PINs begin with a 3. The PIN # I am questioning is 31363D0D. Does anyone have any way of finding out who this belongs to? Any help would be appreciated.