this really annoys me too- and tbh, i'm having a similar dilemma. i lent a friend of mine a whole heap of maternity clothes for her pg, and then once she had her baby, instead of returning them all to me- she went and gave them to another friend of ours who is pg! i couldn't believe it! so now the pg friend is due in a few weeks and i just know there is no chance i will get all my stuff back. i am rather annoyed as there is a dress that was given to me and is very exxy and i honestly have no idea who even has the dress now. it just feels so out of control.
i think you have every right to ask your friend to buy you a new book!