It should be fine because you are not any longer under their sponsorship. I am not sure if the ban applies, check it in the Labour Law, believe it or not, there is a book you can buy for it and they respect it seriously. Another thing is that some of the new employees might insist on your non-criminal record and attesting of all your studies, so as always, it depends very much on your potential employers.

Don´t volunteer too much information. ;)