multiple downloads of the same book -can I cancel the duplicates and what/how am I charged ?

I am new to adobe digital . By mistake I downloaded a book 4 times and was not aware I was being charged? the book come up in "Purchased"- there was no mention of the charge in the process and I never got to any checkout - just to the terms and conditions page for the publisher . I was operating through a university portal - what can I do about this - I am totally lost .i have no idea what I will be charged and obviously I want to make sure it is only once if i cant cancel the whole process.