I've been so happy for those things I have bought from Aliexpress. It was in really good time, and no problems at all. All you have to do, is make sure your seller is trustable, which you can see on the webside. Or you can write to them.
If you don't get your item, you have to "open dispute" before the limit rans out (60 days after shipment is made) or it's to late and you don't get your item or your Money back.
The second problem people has, is that their item never arrives, and if you have chosen free china post air, it might be therefor. If it's an expensive item ship it with an other Company.