Phone, text, or email, they all have a part to play.
AW email for initial contact, request details, phone number etc.
Phone to check all is genuine. Not emailing a pimp.
Text to confirm details, ensure she has your number so she can send you postcode and room details.
I text regulars rather than phone or email. May phone if the response is slow or unclear.
Texts are often preferred on the day. If you ring you will probably get a text back. Emails on the day are a waste of time for the busier SP.