I am doing a Reading IELTS reading test and I don't get the meaning of this phrase "you contact us 30 days in advance of your booking" In this sentence:
"If you need to cancel your stay, you will receive a complete refund if you contact us 30 days in advance of your booking." (see the test)
Say, I wanted to have a room in a hotel on the 1st of November and then I booked the room on the 1st of Sep (I paid $200 dollars to them).
Now, I want to cancel the stay,
do I have to tell them on the 1st August which is about 30 days before my booking (which happened on the 1st of Sep)?
Why do I have to tell them 30 days before the booking happens?? I might not have an idea of booking at that time on the 1st of August.
I don't understand what "in advance of your booking" means?
Why didn't they say "in advance of your future stay"?