I got a response from fasttech today about my purchase and here is what they told me
Sorry for the wait.
We apologize for the shipping issue with Malaysia post. They mentioned that they will ship external battery package via surface mail and ship the remaining packages via airmail. We are still waiting for their definite answer regarding this.
If it turns out that your order is shipped via surface mail after Malaysia Post contacts us then, we will contact you for reimburse the difference in shipping charge and delivery time since you have paid airmail shipping service. Surface mail can take 1-2 months for delivery as Malaysia post reported.
We are not happy about this shipping situation either and would rather they return those external battery packages to us so we can refund you right away. But they choose to ship it anyway whether by airmail or surface mail we don't know yet without confirming with us beforehand.
We sincerely hope that you will receive the order in short time.
While transit time fluctuates, we also have no control over this matter. So, as a way to apologize to our customers, affected customers will receive a credit that is equivalent to 20% of their order amount, with a maximum limit of $50.00 credit per order.
If there is any feedback from the post office, we will keep you informed.
Thank you for your understanding in this case.