Was it sold today? If it is a question related to your trading account at Zerodha, best to shoot an email to [email protected]
Darren,
In F&O segment, the settlement is done on T+1 day. So if you have sold the option today, it will not be considered in your Free Account Balance. It will be considered as encumbered funds. By tomorrow only it becomes your funds. So wait until that to withdraw.
Once you sell an option, your trading account margin balance increases immediately, so that you can use it to enter other positions. There could be a penalty of 1% since you are using the money today, since it is supposed to your funds by tomorrow only. This is levied by NSE not by broker.