We have a received a larger than usual bill from our trunk provider. Apparently, we have placed 3549 calls to Austria and were charged for 3549 minutes of usage. Looking at CDR/CEL logs, we do have a large number of incoming calls from a few different Austrian numbers (about 900 calls ranging from 24 to 38 seconds), but no outgoing calls to that number. The calls are obviously automated.
My question is: How would someone be able to place outgoing calls on our system without it showing up in the logs?
As far as I know, I’ve disabled all transfer functions on IVR (*2, ##).