Hey guys, wondering if there's any general etiquette around booking a girl you've haven't met, at a shop you're not very familiar with?

So I went to True Thai once, had a pretty good time with an older-ish lady. She said come back again we normally have many more girls on, and younger ones too.

I did my research on these forums, but every time I've called to book in a specific girl (recommended on here) I get very abrupt/terse "No she not working today" like I've offended them, and quickly ending the call.

Is it generally better etiquette to ask "Who is working today?" and then request someone?

Or if you're not a regular at a shop, is it expected that you should be booked in with whoever is available and the more popular girls are for "known" customers?

Guessing this kind of varies from shop to shop - but any insights/experiences would be appreciated.

Cheers