Two possibilities. Get the account working again or forget about the account and ask Apple to reset the iPad.
1) For help with an invalid/not-active/not-supported account you need to contact Apple (the people on this board are users like yourself).
To reach Apple Support for an account issue:
1. Click here --> https://getsupport.apple.com/?caller=cups&PGF=PGF63005
2. Select: Disabled Apple ID
3. Select: ”The Apple ID is not active" alert
4. Select: “Continue”
5. Select a chat or telephone call option.
or:
Contact Apple for support and service by telephone --> Contact Apple Support - Apple Support
2) Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. Read the requirements and steps for an Activation Lock support request at: https://al-support.apple.com/#/additional-support and links at the bottom right for the type of service requested. Apple says they may require "proof of purchase documentation” and that you need “proof of ownership documentation”, but does not detail what currently constitutes proof other than it “must include the product serial number, IMEI or MEID.” User reports on this community indicate that typically Apple will ONLY accept an original receipt issued by Apple or an Apple Authorized Reseller. Presumably this is the only kind Apple can authenticate against fraud since Apple is not involved in third party sales. Apple recommends that you "Keep your receipt after you buy an Apple device" --> Keep your receipt after you buy an Apple device - Apple Support
If Apple resets the device this will give you access to the device but won't restore access to the account used to lock it. There is nothing that can be done to expedite an Activation Lock request.
