In general they should accept your 500 euro bill which is legal tender. There is however a common used loop hole that they may exclude some of the more valuable bills because they just don't have the change.

Most counterfeiters don't as much buy 500 euro of goods for their bills as try to get as much change for it, like going to an restaurant and then pay their 10 euro lunch with 500 euro and getting 490 in change.

Most places where you would buy more then 500 euro in goods are very good at detecting counterfeit.

When the objective is to obtain truthful information then torture is less then useless. Nobody would use torture for this purpose. Although it might be a useful lie to pretend you do.

When the objective is to obtain confirmation of what you already believe to be true then torture will be very effective: You can get people to confirm any delusion you might have.