LOTS of older (often contentious) threads on this topic. Some colleges are more understanding on this type of situation and may refund your deposit while others may not.
And then there's my family's experience with Arizona State. My daughter applied there and to a school in Boston. We had paid the deposit prior to her getting accepted at the Boston school and while she emailed Arizona State to tell them that she would not be attending and we thought that was the end of that sine the deposit was supposed to be non-refundable. Low and behold, Arizona State started billing HER for the tuition, room and board. I called ASU and told them that she wasn't coming and they saiud that they could not and would not talk with me about it. My daughter called and told them again but they told her that she had to pay one year's tuition + Room and Board since they had reserved a spot for her. They continued to bill her and after a while sent it to a collection agency that still hounds her 8 years later.
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BLUF: Be very careful about placing deposits with schools and make sure that you know the rules up front. Clearly, ASU expects that payment of the deposit is the same as entering into a contract where you MUST pay $20K+ once you send in the deposit.