The Squeaky Shoe

My mother was given two copies of the same book for Christmas. She was in fortunate possession of the receipt, and decided to return one of the gifts and exchange it for something else.
Mater told me she would return to Easons' Bookstore as soon as possible. Asked for my supposedly apt suggestions about the Something Else, I told Mater the name of a novel I had particularly enjoyed. A little research told me there was a copy in Eason's; I passed the news to Mater, who set off to find the volume.
Mater made an early-bird trip to the city; the sky had a thunderous look about it, and everything, everywhere, was grey drizzle.
Into Eason's she went, the sole customer of the morning, and her rain-slick shoes gave the game away.
Squeak. Squeak. Squeak. Squeak. Squeak. Squeak.
Mater sloshed and squeaked across the shiny floor, to the customer service desk at the very back, to where two idle assistants were watching the approach with interest.
Squeak. Squeak. Squeak.
Mater reached the desk eventually, and wanted to know if they carried the title she was looking for. They did. And could she make an exchange? Of course. They just needed the receipt.
Mater rustled around in her handbag for a bit, hoping she had not faced the rainy day for nothing.
At last, the crumpled paper.
One of the assistants gently told Mater that she was terribly sorry, but the receipt was for the other chain bookstore in the city, a street or two away, and not for Eason's at all.
It turned out that, contrary to Mater's assumption, the book had come from the other store. There was no arguing with that.
Mater returned the receipt to her handbag, stuck the duplicate novel under her arm, glanced at the pair and said, with a wry grin, "I suppose I'll just have to squeak away then."
Squeak. Squeak. Squeak.
The assistants were most amused by the curious encounter- and Mater got her book in the end, after an amount of puddle-hopping.