2 or 3 times per day the customer is getting 'annonymous' calling and it rings 2 or 3 times. if someone answers there is nothing on the line. as soon as they hang out it does it 2 or 3 more times in the next few minutes. is this a problem with the ph...

Has anyone ever experienced the following:Customer is having A4 coming up on the called ID and the phone rings 5 or 6 times and when answered there is no one there. It continues to call back a few times and then stops. Then it will re-occur after tha...