code: function buildFreezeBalance(address, amount, duration) {
    var contract = new FreezeBalanceContract();
  
    contract.setOwnerAddress(Uint8Array.from(decode58Check(address)));
    contract.setFrozenBalance(amount);
    contract.setFrozenDuration(duration);
  
    return buildTransferContract(
      contract,
      Transaction.Contract.ContractType.FREEZEBALANCECONTRACT,
      "FreezeBalanceContract");
  }
docs: Freeze balance
  
  @param address From which address to freze
  @param amount The amount of TRX to freeze
  @param duration Duration in days