To expand on Thebluefish's answer, the form submission process appears to use HTTPS (an encrypted protocol) for the credit card element to
https://connect.firstdataglobalgateway.com/IPGConnect/gateway/processing when I am looking at the page. But this does not mean this setup is safe to use.
The overall setup is very vulnerable and needs to be fixed. I would not submit any credit card details through this service and would recommend that you do not use it. If you absolutely need to use it, you should get a prepaid credit card with just the amount necessary for this service and then use that credit card to minimize the damage if it is stolen. Or if your credit card offers one time use credit card numbers, you could possibly use that (though again, would be at some risk of the one time use credit card being captured and used for a different purchase).
The problem with the page is that everything but the form submission is being sent over unencrypted HTTP, that any network attacker can trivially alter. E.g., an attacker could buy a domain and then change the domain where the HTTPS form is sent to one they control (that may even look similar).
Again, we could look at the page as it renders right now for us and determine it doesn't do any malicious actions. But any router/ISP/computer between you and the server www.myisic.com could change the current content of the unencrypted http page to something malicious allowing your credit card details to be stolen.