Must a debt incurred for alcohol be paid, and is not paying it considered a sin after committing to it?

You are not obligated to repay the debt for alcohol to its seller, nor is it permissible for you to do so, lest you assist him in his forbidden act. However, you should give the price as charity to the poor and needy, so that you do not combine the price with its substitute. It is also necessary to emphasize the prohibition of drinking alcohol, selling it, and buying it, and hasten to repent to Allah.