called on mobile phone

This phone number is my mothers phone number and she gets calls from every state and people are being rude to her telling her she has been calling and harassing them all day. this isnt true because my mother works all day at a hospital and hardly ever uses her cell phone. she told her phone company and they said they couldn't do anything about it. how can someone else be using her cell number calling all over if she always has her phonewith her??? it doesn't make any sense. i wish it would stop because my mother is getting very upset with people calling and cussing her out for something she's never done.

No one is calling.

Received a call at my place of employment - it is a municipality and the Supervisor's Secretary told her not to call. I have no idea who this is.

They call 4-5 times a day!

This number calls me at least a few times a day, even on weekends. There is never anyone on the other line, they leave no message, and when I try to call back, it says it's an international number. Very annoying!!! I set the number in my contact list and put a silent ring tone on it, so at least it won't ring and it will be easier to ignore!

hangs up when call is answered as a business name...