Apple ID no longer exists-locked out of devices
I had an iPhone XR which was linked to an Apple ID which was made when I was 13, that Apple ID is also logged into my iPad and Apple Watch. When I got my iPhone 12 I logged out and deleted the previous Apple ID and made a new one. So now the old one no longer exists, the email doesn’t exist either. But because they don’t exist anymore I can no longer access apps or anything on the iPad or Apple Watch because they are linked to the old Apple ID, can’t log out and it is always asking for the password which I know, but it won’t log in because it doesn’t exist. To sort it I need proof of purchase of the devices, I bought the iPad through Argos about 6 years ago but haven’t got proof of that purchase. The Apple Watch I bought second hand on eBay which I have just a screen shot off the purchase. I don’t know what to do?