How to submit feedback for an Apple Store customer experience

I was directed by an Apple Specialist I spoke with by phone today to submit written feedback regarding a very disappointing customer experience I had at an Apple Store on 15 September.

The Specialist directed me to apple.com/feedback, however I cannot find an option there to provide feedback or make a complaint specifically about an Apple Retail Store or an in-store customer experience.

I have already tried to find the appropriate channel myself, but I'm unable to locate where I should submit this.

Could someone please advise me on the correct way to submit a formal written complaint regarding an Apple Store customer experience, and specifically how I can have it escalated to the appropriate Apple Retail/customer-experience team?

Thank you for any guidance.