If this was the first instance that she couldn't go to the beach, then is no reason to freeze her out. You do that when she does something bad (and if she can't reply fast enough or can't go that is NOT a shit test for which you should freeze her).
Its stupid, and it is like me inviting you to Alaska and then freezing you out for not going.
Try to get her to join you, lets say on Saturday when you go shopping for a gift for a friend or something. And if she can't go, because she has to study or go to work, you reschedule if possible or call her next week.
I have a friend who literally NEVER has time, she's not a bitch or anything, just busy. And I keep inviting her to tag along, but I'm not freezing her out for not going out with me when she has someone or something else to do. You should do the same, take up different things so you have alternative if she can't go OR you can ask her to tag along.
Hope that helps
