If they asked you to call them about it instead of just ignoring your email/fobbing you off, then I'd say it's worth having the discussion with them - clearly the issue is down to the tyres and not the car, after all. You never know what they'll say/do/offer.
At worst, could you sell them as slightly-part-worn-but-pretty-much-brand-new, take the hit versus what you paid, and then get some Contis?
At worst, could you sell them as slightly-part-worn-but-pretty-much-brand-new, take the hit versus what you paid, and then get some Contis?