Understand, if you are seeking a technical solution, more specifics are required. Namely, which carrier, phone, prepaid vs postpaid service. Tracking such calling activity would be possible if you can log in at a carrier's site and view the call logs. ATT & Verizon both offer this on their customer portals, btw. Free to access. Call customer support for your carrier for more info on this/obtaining login/password.
There's also a small possibility that your line/number is being incorrectly switched to another person's line. Less common of late vs the older cellular systems, but still possible.
Question: are you in possession of your cellular phone 24/7? I.g. do you ever leave it on your desk at work/in a purse that's unattended while in meetings or visting a restroom/going to lunch? There might be a simple human solution to your dilemma. YMMV.
My exboyfreind stole all my personal information and I am worried he has my phone calls picked up on another phone. I have had many of my clients tell me someone else answers my phone sometimes and tells them I left town or that I am no longer around. Is it possible for my phone calls to be rerouted without my knowelege? I am the only one that ever answers my phone so when clients tell me another woman sometimes picks up It just doesn't make sense to me. I have heard this from too many clients to think that its just a unexplained fluke. If anyone has an explaination for me I would really appreciate it.
Thanks
bbboorose

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