My Upstox available funds suddenly became 0 without my knowledge. What happened?

SEBI has mandated all stockbrokers to settle the accounts of the clients every 3 months. To give effect to this requirement of SEBI, any balance will get credited to your registered bank account.

For Securities, please refer to this FAQ  https://www.nseindia.com/trade/members-faqs-actual-settlement-of-funds-and-securities 

For Commodities, please refer to this FAQ  https://marketing-creative-and-docs.s3.ap-south 1.amazonaws.com/MCXINSP6342019+-+Settlement+of+Client+Accounts.pdf