First of all, stop buying Seagate drives.
Find out if your drive is under warranty:
Warranty Validation
Then check out how to initiate an RMA:
Data Overwriting Process For Returned Products | Seagate
Find out where your closest warranty return centre is:
보증 지원 연락처 - 아시아 태평양 | Seagate
(Lucky, there's one in Thailand, but who knows how reliable and responsive they are).
The same applies to Tao's question.