The email Im trying to change to was in use (by mistake), I removed its account
If you have deleted it, it is no longer valid, it simply no longer exists and it no longer works.
To understand about a deleted Apple ID, see the Apple articles below:
Read carefully what happens if you close and/or delete your 'current' Apple ID.
How to delete your Apple ID account
How to delete your Apple ID account – Apple Support (UK)
Understand and control the personal information that you store with Apple
Understand and control the personal information that you store with Apple - Apple Support
You need to contact Apple for help -> Contact Apple for help with Apple ID account security
Contact Apple for help with Apple ID account security - Apple Support
You are sign in here . . . with your Apple ID & Password.
Your Apple ID is the personal account you use with all Apple products and services. It includes the email address and password you use to sign in, as well as the contact, payment, and security details that you use with Apple.
You can’t merge multiple Apple ID accounts.
It is may be to late for you because you have removed.
See this Apple article: Change your Apple ID
Change your Apple ID - Apple Support (SG)
Then see this Apple article: What to do after you change your Apple ID or password
What to do after you change your Apple ID or password - Apple Support
You can also contact Apple support for help, -> Get Support (apple.com)
You have to show proof of ownership of your product, provide all documentation showing your purchase of the device.
If you do not have additional proof of ownership, contact the reseller. They may be able to provide the original purchase document.
Once Apple receive your proof of ownership, Apple will further review your request and provide an update.