Phone ****** from inside Mcdonalds

My phone was ****** from my pocket inside Mc D waterfall, my food was delayed badly and there was no security available on that day, i am trying to contact the store to get footage but no one is bothered, how on earth do we feel safe? because of the delay i lost my phone which is 28k, do you guys can help me or do i need to fight legally with you guys ? thank you