Aishah - who has only disclosed her first name for safety reasons - ordered the drink at a Starbucks inside a Target in St. Paul, Minnesota, on 1 July.
In the coffee house chain, it is standard procedure to disclose your name when ordering a drink, with staff then writing it on the cup. But the 19-year-old - who was wearing a hijab - said she hadn't finished saying her name when she noticed the barista writing something on her cup.
"When I first received the drink I was in shock that in this day and age something like this could be written," Aishah said on Monday at a press conference held at the Minnesota chapter of the Council on American-Islamic Relations' (CAIR-MN) offices in Minneapolis.
"I felt humiliated, I felt enraged, I felt belittled."
Aisha questioned the seemingly Islamaphobic message - ISIS being a commonly used acronym for the Islamic State terrorist group - and a manager subsequently defended the staff member, responding: "What's the issue? People get their names wrong all the time."
Aisha was given a new drink and a $25 (£20) gift card before she left the store, but she wants the barista and the manager to be fired and employees to be thoroughly vetted and trained in future.
Speaking to the Sahan Journal, she said: "I felt a lot of emotions because we're at a time when people are protesting injustice all over.
"All these protests and all these people who are using their voice for a change. To me, it felt like in that moment, we're doing all of this for people who don't even care, or who are going to look the other way."
Jaylani Hussein, the executive director of CAIR-MN, added that the group would likely hold protests outside the store if Target did not take decisive action.
A Target spokesperson said: "We are very sorry for this guest's experience at our store and immediately apologised to her when she made our store leaders aware of the situation.
"We have investigated the matter and believe that it was not a deliberate act but an unfortunate mistake that could have been avoided with a simple clarification. We're taking appropriate actions with the team member, including additional training, to ensure this does not occur again."Featured Image Credit: PA