Question: I'm submitted my windows 8 metro application in windows store before 2 months ago. In my application i included advertisement a part and it will showing. but before 5 days the ad will not showing in my application... i can't find any solutions....

help me.

thanks in advance.

Answer: 
Ads are only appear when they exist, if there is no ads for your region no ads will be shown in the app.
I'm sure that you have impressions, you can check that on your pubcenter account.
Ensure you have defined the add height and width, as per the settings in pubcenter