These guys are pulling the numbers from some database, they will try and convince you that your computer is infected/running slow so that you allow them remote access via some form of remote. Under NO circumstance listen to them. I have been in the IT field for 12 years now, and there is no magic company that will contact you to fix your PC. This is so they can get into your PC, and gain access to personal info such as user names, passwords, bank info etc. If they call, kindly tell them to sod off, and go on with your day.
Call from Adams Zennia, about the third one this week. Never leaves a message and since I do not know any Adams Zennia from Tennessee. I will not answer. Big scam buy reading the other posts here.