It’s generally a bad idea to create and use a different AppleID. Notwithstanding the loss of access to paid Apps, Services and Subscriptions (these being forever linked to the AppleID from which they are purchased) doing so creates all manner of difficulties - such as the issue that you now have. It’s always better to update your AppleID account, keeping primary/secondary email addresses, trusted phone numbers and security details current.
As described, you have unwittingly created a situation that requires some care to unravel. Perhaps the easiest route to salvation is to initially concentrate on recovering access to the original AppleID account - as this will be key to resolving the Activation Lock.
Before proceeding, perhaps review these Apple support pages that outline the Activation Lock - and the only mechanisms by which it can be turned off. These will provide essential understanding of how to deactivate the Activation Lock that is currently inhibiting progress:
https://support.apple.com/en-us/HT201365
https://support.apple.com/en-gb/HT201441
If you have forgotten your AppleID or associated password, these can be recovered here:
https://iforgot.apple.com
To recover your credentials, you’ll need access to one of the following:
- Your primary email address mailbox that corresponds with your AppleID
- Any of the secondary/recovery email addresses that should be configured for your AppleID account
- Any of the trusted telephone numbers (fixed line or Cellular/Mobile) that are associated with your AppleID
Unless you AppleID account has not been fully/correctly configured, or has been seriously neglected, recovery of the AppleID and password should not be difficult.
More information about recovery of your AppleID:
https://support.apple.com/en-us/HT201354
More information about recovery of your AppleID password:
https://support.apple.com/en-us/HT201487
When you recover access to your credentials, you should sign-in to the AppleID account from a web browser - from where you can remove the iPad (that is currently Activation Locked) from the account. While you’re there, you might consider the ongoing use of the account - updating and verifying any email addresses and trusted telephone numbers as needed.
https://appleid.apple.com
Once the Activation Lock has been resolved, you’ll need to prepare the old iPad for reuse:
What to do before you sell, give away or trade in your iPhone, iPad or iPod touch – Apple Support
I hope you find this information and guidance to be helpful in resolving any difficulties.
