I have a trigger and a rule that fire regularly using cron.
In the develop UI I disabled the rule, but it all appears to still be firing and hitting my action...
You can install the OpenWhisk CLI and check the status of your rule there.
If the rule appears to be disabled there as well, we have a bug in the system itself. It'd be great if you could open an issue then here: https://github.com/openwhisk/openwhisk/issues.
As for the UI, you can request help via the Support tab in the top-right corner.