You need to seek counsel from an attorney in your area that deals with unemployment insurance issues asap and BEFORE you speak with them on the phone.  The key to collecting unmeployment is that you are looking for work and ready, willing and able to work.  You stopped looking and you told them that and they stopped paying and now want money back.  There may be a point in time that you can look at and say this is when I stopped looking for work and may be it was way after you started school (look again at what it says o the website about going to school and collecting).  I just do not think that you should speak with them until you know all your rights. Get help.  Good luck to you.