Was there an agreement or terms and conditions document which set out what the details under which you paid the deposit? A properly worded agreement should set out the conditions for refunds and timescales for doing so, along with what penalties apply, as these would apply in the inverse situation that you didn't pay any balance due if you had taken up a place on the course. For an organisation such as Coventry University there will almost certainly be such a document. I would look through all of your correspondence you had with them about it, emails, letters etc and find the document. This should then guide you with what your next steps are, sometimes a contract will require a formal notification that you want a refund - so you need to see what the terms are and if there are any actions on yourself prior to a payment being made.