iPad 6 disabled - Could you help me to recover it

Dear Technical Team

I have an iPad6 which was given to me as a gift from a family member back in 2014. However recently it is disabled and I am an able to use it. I went to the nearest apple store here in London - West Field Shopping Centre and I was asked for receipt and a serial number for them to recover my iPad. I am an able to find the receipt however I offered them my identity card incase they are worried it is stolen.

However they declined. I don't know what more I can do.

I need you help.

Thank you