Issues with e-mail

I am a student and I have subscribed the student adobe account. I have inserted my student e-mail (the institution e-mail), but I have forgot to put it right: instead of "...@my.ipleiria.pt", I have put "...@ipleiria.pt". I have tried to fix this but the website keeps telling me that "...@my.ipleiria.pt" has already been inserted. After this, I have had several issues, because I couldn't access my adobe account or change to another e-mail. After trying a lot, it was allowed to change my e-mail through Chrome, and this time I have changed it into a Gmail account. My problem is that I can't change it back to "...@my.ipleiria.pt", because it keeps telling me that that e-mail has already been inserted and now I am afraid of loosing my student discount because Gmail it is not an academic institution :). Can somebody help me with this? Thank you, in advance.