I have stopped with waswas questions since you pointed it out before. I get money to study but taking it means that if I earn too much from a job they could demand payment back + riba. Is this money haram to take given it is not a necessity? What about the money I earned from this when ignorant?

Ustadh AbdulAziz al-Haqqan

Do not take part in that which involves riba, don't even get close. As for what you already took, you do not have to return anything.