liquidation rules

Friends, I can not find the necessary information in the rules. I borrowed 1800 USDT against 3000 USDC a year ago
Now I have no way to return 1800 USDT to the system

  1. What will happen? I have 3,000 USDC being liquidated?
  2. Is it possible to pay 1800 USDC for 1800 USDT?