Return service so bad

I am big fan of them I always buy from them and they deliver quickly but this time around I bought a sneaker and the size was big and I logged a return and they came collected them and they rejected it says its dirty and all of which that is not true I only fitted the on top of a blanket because the shoe looked big and I said OK they return it back to but up until now I haven't received it and I have been following up countless times with them