Integrated Chinese Vol 4 Workbook (English and Chinese Edition)

We purchased this for a course my son will take in September. We thought he would be able to use it over the summer. However, this needs audio and the only method for getting audio is to purchase a subscription online! Had we known this, we would not have purchased this book now and instead considered both the textbook and the workbook online versions. It costs $80 for a year subscription for the textbook basic and $115. I would think that if a person purchases the textbook and it is USELESS without the audio that they would alert a person to that fact. The website asks for a "promotional code" for a discount and the books don't even give one for the person who purchased their material. I am not happy!