It is Guardian...ours was a courtesy call to verify for installation but I am guessing if they are calling you at 3-4 AM, then they likely have your number on file incorrectly for someone else's account. If it's a wrong number, call them (888-854-8773) and let them know! I'm sure they don't mean to intentionally disturb you!
I have been getting these calls for nearly 2 years and have told them to remove my name and number from their list. They keep calling anyway. It is Guardian and they have not taken me off their call list despite repeated requests
I am on the NO CALL list and this company continues to call me. When I answer, they hang up. So, now I don't answer the phone anymore. I have to pay now for an extra service with AT&T to block this number. Jerks!