u/IndividualDepth382

I already registered on jia for ssb but I don't know how come my number got changed over there but I again updated my number.. Will there be any problem and what is the last date to register on jia.. Help me pls

Where can i get some best ssb preparation books pdf.. I really need it.. I cleared the nda written but I cannot afford the books.. Pls let me know if anyone has any idea.. I will be grateful to you