Why did Mary begin to compulsively check the mailbox after Father's Day?

After Father's Day, Mary made every attempt she could to get into contact with her father -- she tried, unsuccessfully, to make a collect phone call, and she made him a Father's Day card that she sent through the mail. Immediately after mailing the card, Mary compulsively checked the mailbox to see if her father responded, but after a few weeks, Lecia lost the mailbox key and Mary found it to be too much trouble to wait at the counter for the mailman to arrive, so she gave up waiting totally.