Thanks for your response @King_Penguin. Here is the summary:
I bought a new iPad in 2014. Shortly after, i changed my Apple ID on the device. I received a mail acknowledgement from Apple confirming change of id. I started using the new Id, change password, and sign into apple applications etc using the new ID.
I had to do a reset last month but i can't activate the device cos it's iCloud locked. Unfortunately the new Apple ID i changed to which i've been using for more than 2yrs now cannot unlock the device, neither can d old one do. To make matters worst apple server can no longer recognize the old Apple Id.
I've been to d Apple Store i bought the device, tendered my purchase receipt + the device but they said i need to remember the Apple id & password.
I've been into chat session with Apple Support on Twitter, send them all my details, device serials, screenshot of confirmation emails from apple confirming Change of Apple ID, change of password of the new Apple ID i received from Apple for both old n new Apple accounts.
Apple support keeps sending me a link to contact Apple support nearest to my location that they don't support my location (Nigeria). Unfortunately, there's no Phone contacts for voice call or chat link for my location on that link. Instead, d link provided by Apple support keeps taking me round a circle. I have asked Apple support to kindly provide me with a contact i can reach out to from my location since the information is not available on that link but they've stopped responding to my messages.
Right now am too disappointed. Why must i bear the brunt on Apple's failed system? I changed my apple id email and received confirmation and now the new id cannot unlock the device neither can the old one.
What do i do? How do i contact Apple Support in Nigeria? How do i activate my device?