Cancelled, unfilled orders are pruned hourly by the engine for performance optimisation purposes which is why they don't show up in your Order History.
Specifically, terminated orders will be pruned if they satisfy the following conditions:
You should still be able to find the cancelled/rejected order through GET /order with filter {"ordStatus": ["Canceled","Rejected"]}.
This website is operated by HDR Global Trading Limited, a company incorporated under the International Business Companies Act of 1994 of the Republic of Seychelles with a company number of 148707 and registered address at Global Gateway 8, Rue de la Perle, Providence Mahé, Seychelles (“HDR”). HDR wholly owns BitMEX, a Bitcoin-based trading platform.
Access to trading or holding positions on BitMEX is prohibited for any person or entity that is located, incorporated or otherwise established in, or a citizen or a resident of: (i) the United States of America, Québec (Canada), the Hong Kong Special Administrative Region of the People’s Republic of China, the Republic of Seychelles, Bermuda, Cuba, Crimea and Sevastopol, Iran, Syria, North Korea or Sudan; (ii) any state, country or other jurisdiction that is embargoed by the United States of America; or (iii) any other jurisdiction where the services offered by BitMEX are restricted (collectively “Restricted Jurisdictions”). If it is determined that any BitMEX user has given false representations as to their location, incorporation, establishment, citizenship or residence, or HDR detects a user is from a Restricted Jurisdiction as described above, HDR reserves the right to immediately close their accounts and liquidate any open positions. HDR may, in its sole discretion, implement controls to restrict access to the BitMEX trading platform in any of the Restricted Jurisdictions.