My roommate is leaving and wants to sublet the apartment. She liked someone and wanted them to move in but I wasn't a huge fan. I found someone else that is moving in. The problem is that my roommate wants the new sublet to pay 1/2 months rent (roughly $300) when the sublet will only be living in the apartment for 3 days this month (moving on March 28th). Her and I already paid rent for March. She is moving into her new apartment this weekend (8th and 9th of March) and said she shouldn't pay for all the month because she is moving out early. She isn't even paying rent for her new place this month (she got a month free for signing on for the new apartment). I refuse to have the sublet pay that much for 3 days. If I tell her no about $300 can she sue me for 1/2 months rent? Can I tell her no?
Also, she is on the lease until the 28th of March until the new sublet moves in.

