It is a scam. They are trying to swindle money out of you. Never allow anyone to take over your computer. Though probably they don't install software, just say they have and have 'fixed' the problems, and charge you for it.
SSN
very simple, most modem company's provide cli program with their modem cd. Just install it and display caller no. on your computer monitor.
If a radio station is giving away a t shirt to every third caller and a ceramic mug to every tenth caller then the 30th caller will get both prizes.
When a radio station announces that they will give a ceramic mug to every tenth caller and a tee shirt to every third caller, both prizes will go to the 30th caller.
its a stalker
Caller ID allows the receive of telephone calls to determine who is telephoning them before they answer the call .This in turn allows the user to decide whether or not they wish to answer the call. There are no notable differences between caller ID and BT caller ID other than the BT service is included in the BT Privacy at Home package.
busy signal
If you have caller ID, call the police and tell them the number of the person who threatened you. If not, I'm not sure.
Yes, as long as you have a caller ID. In phone system such as the IP PBX, you can automatically view the identity of incoming calls into your phone or hear it over the speaker of a computer.
Many VoIP providers (e.g. Skype) offer this service.
The advantage is - you don't need to be there to receive a message. The caller simply records their message at the prompt - and you listen to it at your convenience.
Remote Assistance per A+ book.