Question: how to check if you are blacklisted by ptptn?
Answer: Official Portal of the Immigration Department of Malaysia (JIM) Click here to go to the following page. ... 
PTPTN Official Portal – Black List Review. Click here to go to the PTPTN Official Portal. ... 
Call the PTPTN Careline. PTPTN's official careline is 03-2193 3000.
Personally check at any PTPTN / JIM counters.