Please deactivate the account/release the email as followed steps:
Step 1: Sign into the account, visit [My AliExpress] - [Account Settings] - [Edit settings], and click [Edit Member Profile].
Step 2: Find [Deactivate Account] as below and click it.
Step 3: Confirm below information and submit.
Note:
1. Deactivating your account doesn't mean deleting your account. It will only block the login access of your account
2. You may decide whether to release the email from AliExpress with option on "Release my account at the same time".
3. If you want to delete the account completely, please go to below link for more information: https://privacy.aliexpress.com/
