We have 4 statuses:
1. green: below 80% of the events included in your plan
2. yellow: between 80% and 100%
3. red: between 100% and 150%
4. black: above 150%
When you reach the red and/or the black status, you will receive an email alerting you of your status (the alert shows up also within the dashboard) and the dashboard becomes read-only.
In the red status, tracking links, all associated options and stats continue to work normally, provided you upgrade your profile within 48 hours (as reported within the email).
After this time limit, if not upgraded, your profile can be changed into black status at any time (regardless whether you exceed events by more or less than 150%).
In the black status all options (e.g., conversions, deep links, CTAs) and stats are disabled, all tracking links become simple redirects and stats are not recorded anymore. The only exception is for password-protected tracking links that return a 404 error to protect the destination URL. If your status remains black for more than 180 days (about 6 months), all your tracking links could be blocked and return a 404 error, in other words they could no longer be redirected.
Please note also that the transition from a red state to a black state can take place within the 48 hours time range, if your events exceed the 150% of the events included in your plan.
The events limit, as stated in the pricing page, is meant "monthly."