An important info on posting a postcard

Guys and Gals...today i just got to know that ...if you want to send a standard size postcard..make sure that you have blank space of 15mm on the left ..right and bottom of the card....so that you will only need to pay 20 cents....else you will have to pay 30 cents. Today i got a call from post office asking me to collect back 1200 invitation cards which i send last week behalf of my company. Our postcard size is non-standard and no blank space on left, right and bottom...therefore...need to pay 50 cents. Fxxx the manager...didn't check properly before ask us to send...make me go here go there doing all those donkey jobs. She is the donkey..so she should be the one doing these rubbish.