How do I unlock my account?

If this is in the iTunes/App Store, see the 3rd link.

If your Apple ID is locked or disabled - Apple Support.       

If you have changed your ID or password, have you followed the steps in this article?

What to do after you change your Apple ID or password - Apple Support.      

If you see a message that says 'Your account has been disabled in the App Store and iTunes' - Apple Support.    

If necessary, contact iTunes Support. Either use the form or scroll to the bottom of the page in the 2nd link. Follow through the screens to get a chat or telephone option.  

iTunes Store - Contact Us - Official Apple Support.       

iTunes Support – world wide        

If you are not seeing activation lock, then use:

 If you forgot your Apple ID  https://support.apple.com/en-us/HT201354

You also can use Having trouble signing in/iForgot https://iforgot.apple.com/password/verify/appleid

But, it sound like you are seeing activation lock? If yes, you can turn activation lock off only by entering the correct Apple ID/password combination. The correct combination is the one allowed by the person owning the device. If this combination cannot be entered, then the iPad is useless to you unless there are extenuating circumstances (e.g., you have the receipt for your purchase of the device with its serial number on it or a court order instructing Apple to assist in the provision of access to a decedent’s information from the deceased person's accounts--(see How to request access to a deceased family member's Apple accounts https://support.apple.com/en-us/HT208510) If you have either, contact Apple support using one of these options.

Get a call from Apple support to help solve your problem using this link https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362

Apple ID Support https://support.apple.com/apple-id

Apple ID account security for country-specific and region-specific help https://support.apple.com/en-us/HT204169

Get Support: We’re here to help  https://getsupport.apple.com/. Go through the options to find the best support option.