It's not unlimited as already discussed in this (or another?) thread.
linked right below the plan table.
ACT encourages responsible use of unlimited data by each of its subscribers. ACT believes that even when a subscriber chooses to use the Unlimited plans extensively he or she may not be able to consume the maximum data limit of 3300 GB per month or above as per the tariff plan subscribed (hereinafter referred as "Maximum Data Limit"). Any such usage over and above said Maximum Data Limit will be treated as abuse of Unlimited Data plans by the said subscriber.
linked right below the plan table.