Conversation so far:
What was the beginning of the Sultan dynasty of Madurai for the Madurai Nayak dynasty?
Early in the 14th century, a dispute arose over the succession to the Pandya throne.
Who was the first sultan of the Sultan dynasty of Madurai?
One claimant appealed for help to emperor Ala-ud-din of Delhi, who dispatched his general, Malik Kafur, in 1310.
How did emperor Ala-ud-din of Delhi's general, Malik Kafur, take over Madurai?
Malik Kafur marched into Madurai, sacking the town, paralysing trade, suppressing public worship, and making civilian life miserable.
How was the sultanate of Madurai received by the people?
The Pandyas protested the invasion, which continued for a few years in spasmodic fashion.
What else the pandyas do to get back Madurai from the sultanate besides protest?
The weakness of the Pandya regime caused the neighboring Chera ruler to invade and defeat the Pandya ruler, and he crowned himself in 1313.
Did the Cheras work with the sultanate in Madurai?
This was followed by a Chera occupation. However, the Chera occupation was transitory.
What else is known of the Sultan dynasty of Madurai in the section besides the first sulton, reaction to sultanate, and working with the Cheras?
A Sultan dynasty was soon re-established at Madurai, ruling Madurai, Trichinopoly and even South Arcot, for the next 48 years
What is the significant aspect of the forty eight  year rule of Sultan dynasty of Madurai?
first as feudatories of the Delhi Sultanate and later as independent monarchies.

Question: how did they achieve their independent status?
Self-contained rewrite: How did the people of Madurai achieve their independent status?