I've had positive experiences with AliExpress returns/refunds.
I ordered some 12V LED bulbs - with a B22 fitting. They came with E27 fittings. I opened a dispute, and sent the seller photos of the bulbs.
They said keep the bulbs, we are sending the correct one. They asked me not to place negative feedback, and to close the dispute. I said I would close the dispute and provide positive feedback once I had shipping confirmation. New bulbs arrived about a week later. Happy.
Another one - I ordered some vacuum seal bags - the order got cancelled, refund processed about 5 working days later. Not sure why the order was cancelled, but it looks like AliExpress did it, not the seller.
I have noticed on a few items, the seller saying that if negative feedback is posted before you have contacted them to resolve they will just wipe their hands of it and you will be stuck without resolution. Feedback is obviously really important to (most of) them.