What is the ruling on mixing in studies at English language institutes where foreign women, who tempt students, teach? And is it obligatory to leave these institutes?

For the permissibility of studying with foreigners who do not adhere to any religion or moral code, it is stipulated that such study should not lead to falling into something unlawful, such as prohibited mixing (of genders) or imitating them. If you fear falling into any of that, then you must leave the institute and enroll in another where there is no reprehensible matter. For safeguarding one's religion is obligatory, and whoever gives up something for the sake of Allah, Allah will compensate him with something better.