If you could not access due to some fault of theirs--such as, for example, their website being frequently down or otherwise flawed--then you would not have to pay. Have if the reasons for nonaccess was either your fault (e.g. you had old software or hardware, or a too-slow internet connection) or a third-party's fault (e.g. something was wrong with your internet service or service provider), then you would still have to pay, since the institute is only responsible for issues which are their fault; otherwise, they can hold you to your obligation to pay.