John Lewis (UK) refusing me return because of 'broken seal'?

I purchased iPad Pro 12.9 2020 from John Lewis, simply because it was the quickest (next day) collection from my local Waitrose store. In lock down, Apple stores stay closed and delivery is not next day.

After using it for few days, I don't see any added benefit of it to my existing iPad Pro 12.9 2018, for my use case. I requested return within 14 days and sent it back in its original box and accessories within next 4 days with return confirmation receipt. Today, 4 days later, I have been emailed that they refuse to refund because the 'seal is broken'/'item used'. How on earth am I suppose to know if an item is suitable for my needs unless I give it a test run for at least few days???

Clearly, this is against the Apple UK Legal Returns Policy. So why a (longstanding and reputed) retailer allowed to disregard it? On my part, I am buying an Apple product (not a John Lewis one).

I have been Apple consumer for longer than I can remember being in it's ecosystem. This is the first time, I have been refused return for such unreasonable reason by a third part retailer.

Please advise and help or else we should never buy Apple products from non-apple store???