1- China Post Ordinary Small Packet Plus : Unregistered and can only be tracked till "line-haul / Shipment accepted by airline". Package can easily get lost in transit because no record for it is maintained.
2- China Post Registered Airmail: Traceable till the package reach your city. You will receive your package guaranteed because it is a registered mail and postal service has to deliver it to you one way or other unless our customs stop it for some genuine reason.
3- Singapore post: It's also kind of registered post and traceable till Pakistan. You will get your package for sure.
4- Ali Express Standard Shipping: At the back end, It is China Post Registered Airmail. Your items will reach you guaranteed. Ali Express handles your package shipment.
5- Malaysia Post: Haven't tried it yet. But I am sure you will get your package.
Use China post registered airmail or Singapore post to make sure you get your items. If you use "small packet plus" and it get lost in transit, act responsibly and do not demand refund from seller because he is not running a charity to return your money just because you are miser enough to not spend a dime on using better shipment method. (Sellers only offer small packet plus shipment method to keep the product price low.)
Most sellers are already offering free shipment via China Post registered or Singapore post. So if you see that your package has not reached pakistan and it is lost in China, you should ask a refund. But if it has reached Pakistan (since these shipment methods are traceable) then do not demand refund as our customs champs might have held that for some reason. Visit customs office in your city and get information about your package.