Employment problem

Hello Sir, I did my diploma in ECE branch after passing my 10th class. I have applied for postal assistant job in andhra pradesh postal circle and qualified the exam process and got the provisional allotment order to attend for document verification. During document verification they rejected my candidature stating i do not meet the required qualification. As per the notification the required educational qualification is 10+2 std or 12th pass from a recognised university excluding vocational course. As per G.O Ms.No.112 of state govt. of Andhra pradesh, Diploma is equivalent to intermediate. I took the same to the head post office of hyderabad and they are not ready to accept this as they said this G.O. comes under state govt. and postal department is a central govt. undertaking. So, some one please tell me whether i am eligible for this post or not. And also please tell me how to proceed further. I would be very grateful if anyone let me know the solution for this problem. Thank you in advance.