Any way to remove an Apple ID from an iPhone without going through the Apple process?

I've got a refurbished phone so the IMEI on the back is different to the one in settings. I tried removing the Apple ID by contacting Apple and sending them the proof of purchase but the data don't match with their records so they refuse it. They want the original proof of purchase but I can't get hold of it. Is there any other way to get rid of the Apple ID if you don't know the Apple ID and password that was used.

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