Thank you for your email we are sorry to hear you are thinking of cancelling your booking with Unite Students. Your liability for any future payments depends on your circumstances as you are outside of your cooling off period, and past the cut off of 1st of August. As such you are liable for the rent until a replacement tenant is found. (I refer you to the cancellation policy on the tenancy agreement you signed, a copy of which is available here http://www.unite-students.com/cancellation-policy).
Unfortunately as it currently stands there is no way we can suppress any upcoming payments as a replacement tenant is not in place. If you do still wish to cancel with us, please have replacement tenant to contact us on 0300 303 8645 or +44 117 302 7497 internationally in order to book your room. We will release you from your contract with us once your friend has returned her tenancy agreement and paid the required £250 deposit.