Is it permissible to benefit from money acquired by hacking foreign banks and to purchase electronic devices with it, provided customs duties are paid on them?

What you did by accessing banks and using people's credit cards is considered devouring wealth unjustly, which is theft and fraud. You must repent to Allah and return the money to its owners, or spend it on charitable causes if you are unable to return it. Paying customs duties on what you took in this manner is invalid and entails nothing, as it is the act of an usurper dealing with usurped property.