If you're on the enterprise license, this means that you've been over the limit 5 times, and if you're on the free license, you've been over the limit 3 times.
If you have an enterprise license, you should file a support case describing why you've locked yourself out of the product, and you will probably get a reset-key to remove the violations.
If you're on the free license, this is not as likely to happen. In that case you'll have to wait until the oldest violation falls out of the rolling 30 day window, which could take anywhere from 0-27 days, depending on when your violations occurred.
Regardless, indexing will continue, and you might want to decrease the amount of logs that Splunk indexes, in order to not get more violations. Or consider a license upgrade.