Does seem a bit odd to me considering the use the Remedy is designed for (it’s not just a long travel XC bike!) that you have managed to cause such obvious damage just by being a bit heavy and not particularly a smooth rider, yet no big drops and the like.
The problem you’ll have if selling the Remedy is that anything you buy that’s more “fit for purpose” is going to be heavier and not as good at going uphill quite frankly. If you were asking me what bike to get yet I didn’t know you had had trouble with a Remedy, I’d actually be suggesting a Remedy right now as I think they’re possibly the best combination of weight/burliness/efficiency/price for a full sus bike on the market right now. So it’s a shame this has happened! The fact they’re not warrantying the frame, but only replacing it on a “customer service issue” does worry me though. What use is a warranty if the manufacturer just say “rider is too fat/clumsy” every time they have a frame back? NONE!
Anyway, if you sell it (it ain’t worth £1500!!! More like £750 as BillOddie says) look at something like the Giant Reign or Reign X. Giant’s ALWAYS come up a bit overbuilt for their use (and subsequently you don’t see many broken!), they ride ace (I LOVE my Reign X), still climb very well, descend very very well etc. Just a bit heavier than the Trek really!