I have a Red Kite Cube stroller that I bought new, my daughter absolutely loves it and so do I, but the back two wheels seem to wobble from side to side and make a loud clicking sound every time I use it?
If this is happening, it means something - probably the plastic hubs and joints/housings got loose or broken inside. This is not a thing you can repair. I would suggest claiming your warranty at the shop/retail you bought it at; they should replace the frame.
I am sorry not to have better news, but really, this problem happens with cheaper plastics or when a stroller is overloaded. You will need stroller service repair/replacing at the least, but almost surely, the whole frame will be replaced (otherwise, it will just get worse to the point of your rear wheels being lopsided to the side and later potentially break off).