Today I learned about a new scam. So, when a sign is posted in front of a property that states it is protected by an alarm company there are scammers who will send letters to the individuals living in those properties who may or may not be the homeowner asking if they would like a discount on their alarm and to please call the number in the letter.
If the individual calls that number they are vulnerable to being asked for credit card information again, verification of their credit card or other financial information.
These scams are all different. Could be a special on servicing of the alarm, a problem with an existing credit card or a variety of different requests anything to get you to call. It is also possible to determine who has an alarm system on the internet and for them to use those lists.
Before calling any phone number in a letter you receive it would be prudent if you call the alarm company directly to verify that they actually sent you the letter.