I would urge you to try and get the college to recognise that you left in October as it will have implications much greater than for Jobseekers purposes - if you leave a course before 31st october you are would not count as having had free fees so would qualify again for a fee free first year if you returned to college at a later date. The fact that your grant was stopped implies that someone in the college/grant authority knew you were not in attendance and there will be records somewhere to support this, if you had Jan exams you would also have missed those which will again be noted in registers. The admin office associated with the department you studied may also have records of non attendance...
You should of course have informed the college of your 'dropping out' so approach them with that in mind! With respect to Jobseekers - what have you been doing since October, if working daytimes etc would that be proof that you were no longer in college? Good luck!