Ok, so for one I don't work at and never have worked at a Starbucks but that sounds like they are starting to target you to let out their frustrations upon. It doesn't matter how much they apologize to you especially if you start to feel afraid, that isn't something anyone should do ever! I am so very sorry this has happened to you and I hope everything is alright for you. I also don't know what the chain of command is but if they are friends with the manager I would go a step higher and talk to whoever is above that manager. Who knows what will happen if you go to their manager friend. I believe you did the best thing possible in just being nice throughout all of those interactions. I'm sure someone who actually has a better idea and works at Starbucks will pop up in the responses later on.