You won't compete with the social media platforms
The best educator in the world is unable to compete against Facebook and the other social media platforms that students love. Don't even think about it and therefore start by removing the cause to eliminate the competition, which remains standard practice elsewhere. Banning mobile phones in the classroom initially produces effects similar to being taken off life support, yet generates immediate positive results. The usual suggested ground rules of clapping your hands for silence and expecting positive results based on the belief that 16 year old testosterone fuelled teens hooked on Facebook will suddenly behave as responsible mature adults is about as naively optimistic as it gets.
Similarly, asking the school to intervene in discipline issues is a wasted endeavour as they haven't a clue either and it's why they hired a foreigner, in the forlorn hope that if all else fails you'll substitute the missing entertainment link.
Trevor