Things should be paid in kind. Pay true help with generous return, worth with worth and politeness with politeness. But to a shameless claim like sand in your bowl of rice give an answer like a stick dragged through swampy mud.
This reminds me of a story:
A poor man passed by a shop where appetising shish kebab was roasting on a turning rod and koftes were frying with irresistible aromas. As he could not afford to pay such delicacies, he took out of his bag a large piece of bread. With his nose immersed in the delicious smell, he ate his loaf dreaming of lavish feasts.
The shopkeeper observed him for a while and then requested him to pay for the treat:
"Your bread tasted better in the smell of my kebab, so you must pay," he said.
As the man refused to pay, the owner dragged him before the cadi, who happened to be the Hoca.
Nasreddin listened to each party, with attention, and resolved quickly:
"Goods enjoyed must be paid. You, the client, present me your purse."
With tears in his eyes, the poor man handed the little bag containing all his money.
"Now you seller, how much is one good treat of your kebab worth?"
"Five aktche, Judge"
The Mullah took five coins, all there was, from the man's purse and called the merchant to sit by him. He rattled the coins in his fist and asked again:
"Do you recognise the sound? Is it good money?"
"It is", replied the seller.
"Then you are paid in full" decreed the Hoca. "For the smell of food you have right to the sound of money."