Short answers, pulled from the story.
Rafi ud-Darajat sat on the Mughal throne in 1719 as a figurehead for two powerful brothers. Sayyid Hassan Ali Khan Barha and Sayyid Hussain Ali Khan Barha had deposed emperor Farrukhsiyar with the help of Maharaja Ajit Singh and Balaji Vishwanath.
On the 18th of May 1719, less than three months after accession, Rafi ud-Darajat's uncle Nekusiyar claimed the throne. He assumed power at Agra Fort believing he was more eligible for the post.
Rafi ud-Darajat returned a favor by granting Chauth and Sardeshmukhi rights to the Marathas. This agreement covered six Mughal provinces across the empire where Mughal officials collected taxes and then handed them over to the Maratha leaders.
The Amir ul-Umara received him respectfully before confining him at Salimgarh Fort. Nekusiyar died there in 1723 while still imprisoned.