Is it permissible to utilize the remaining 7,0 euros from a language study grant by withdrawing it through a school that agrees to release the amount in exchange for a 50% commission, given that the questioner intends to use this money to repay debts?

The granting entity did not pay the money for you to own it; rather, it is a fee for teaching the language in schools. If this is the reality, then that money is designated as a fee, and you do not own it. If you did not teach in the schools, then it is obligatory to return the money to the granting entity or to inform them of the truth. If they permit you to own it, then that is permissible; otherwise, the money is theirs. Your being in debt does not make it permissible for you to take someone else's money to pay off your debts.