Section 6 is a summary remedy focused purely on possession, ignoring questions of title, and the Act's own wording tells us exactly what procedural route it uses.
The correct answer is Suit.
One clean way to answer this is to notice that Section 6 deliberately allows the dispossessed person to recover possession notwithstanding any other title that may be set up, meaning even the true owner cannot defend by pointing to their title, they must first go through the proper legal process rather than taking the law into their own hands.
Given this purpose and the section's own wording, the dispossessed person recovers possession by Suit.