What is the dispute between Reliance and Amazon over Future Group?

Amazon is seeking to stop Mukesh Ambani's Reliance Industries from acquiring Future Group's retail, logistics and other assets for $3.4 billion. Amazon said when it acquired a stake in Future Retail's promoter Future Coupons last year, it had clauses barring the group from selling retail assets to entities including Reliance. The US company accused Future Group of violating that agreement.