If your trade(s) have been closed by us it's likely due to you being on a margin call. To prevent you from incurring a negative balance, we can partially or fully close your trades if your account equity doesn’t meet the margin requirements.
Please make sure you maintain the necessary capital in your account to keep your trades open.
If the position closed is in a share, then it’s possible that the company has undertaken a corporate action event. Please check if you have received an email explaining the detail on this, as each event can vary in nature.