I think if someone has a debt that he cannot afford to pay and if Riba is accumulating..then in this case to save someone from Riba ...the person that has accumulated Riba because he has a lot of money in the bank ..should be allowed to help that person and save him from Riba .
I'm just thinking this way it will help the person and free him from debt
Wa 'alayk as-salam,
Since the activity/competition was something haram, then taking the prize money is also haram, I would simply try to refuse it, you won so it's your choice, they shouldn't be able to just forcibly give you the money against your will..
As for practice at the tech company; if there is nothing haram involved then it's your choice