Odd Phone Call

This afternoon somebody called me from a German Cellphone Number. When I picked up the phone, the person hung up. I did not recognize the number and called back. Nobody picked up. 13 hours later, at two in the morning I received another phone call from the very same number. When I picked up the phone some woman asked me why I called her number. I told her that I received a call from that number but she insisted that she had never called me and that it must be a mistake. I asked her if she was aware that she had called a number in the US and that it is very expensive but she did not let me talk and told me that she was exercising and could have not possibly called me. I again tried to tell her that it is like two in the morning and she's made a phone call to the US. It clicked and she simply hung up on me. 

There are some weird people out there, I swear...