Excursion -trying to book online and no luck

[tofubeast]

Hi. Our cruise is next month, and I am trying to purchase an excursion in advance. The listing pops up and it allows me to look at the description and so forth for each excursion.  However, no matter if I try to book it via the app or on the website when logged in, there is no purchase button to add it to the cart and actually pay for it.  I tried going around about way on the web and was able to get a purchase button, but it did not work when I clicked on it. 
 

Unfortunately, the website and the app has its share of wonky problems   Has anyone encountered this issue? Is it just a glitch and should work in the next day or two or three? I should add that when I looked at the spa and drink packages as well, there is no button to pay.
 

Also, I noticed that some of the excursion prices fluctuate even by the hour.  I have taken screenshots of a few excursions and noticed they go up and down by $10 sometimes throughout the day.    🤔