My stroller was broken at the part of attaching the carrycot and sitting part. Do you have parts of stroller to change for?
I am sorry to say that, 1) we don't sell anything here on Strollberry, so I cannot help you there, and 2) if the central attachment point is broken, even if you had the plastic part, you'd probably not be able to fit it on and repair your pram. With such damage, the stroller is not safe anymore and cannot be repaired. Your only move now is to get a new stroller, or try and claim your warranty at your seller's if you are still covered by that.