I have a hard time ordering food myself sometimes ( one time a taco bell employee thought I was having a stroke LOL) but I try and if my sister is there with me and I’m having a bad day she sometimes orders for me. But this is unacceptable from anyone, never let anyone belittle you and treat you less than a human just because you stutter. You are an amazing and strong person, no matter what she says she is showing how much of a trash person she is and you deserve better. You are great you are amazing and a stammer doesnt define you only if you let it. I felt your pain reading the hard blocks with pressure. this and all I can say is a quote “we accept the love we think we deserve” and I hope you realize you deserve the world and much more than someone who treats you like this.