If the available data transfer limit is exceeded, the account is blocked. The website may display the message '509 Bandwith limit exceeded'
For this reason, it is worth controlling the transfer consumption through the statistics available in cPanel. The bandwidth statistic is responsible for the transfer.
If you have exceeded the transfer limit and you do not want to wait until the first day of the month for the limit reset - you can enlarge your hosting account - it does not require interfering with the server content, after logging in to the Customer Panel, use the Enlarge option and pay the difference to the current subscription.