Ermm, you got watch Mentos ad...?
Next time just xiao1 sa3 yi4 dian3 take off your shoes and walk
coolly to the nearest available place selling shoes, then let the
salesperson know your predicament. I'm sure they'll help you find a
comfy pair of shoes at a reasonable price even if the shops are
about to close. 
The girl was a bit rude, but maybe your request came as a shock to
her (after all this kind of request we don't come across everyday)
hence the curt response.
