She didn't want me to call her during lunch time.......

Dun understand.... She said is a waste of money.... I can tell she enjoyed it when I called her during lunch time. I can tell she's happy... But why ask me to stop??? I dun understand.... I really dun..... I know she sometimes have to buy things, and she walk while she talk... which could be a bit breathless.... But still...... I really dun understand..... I wonder if I had skype and I can call her for free.... would she say that to me??