received copy of appointment letter intentionally missesed by gov. office assitant

i got an appointment letter of a gov school and it's received copy is also submitted in it's department head office but due to some reasons i request to officer who alotted us school to change my school. He consider my request and allowed it to change. But this time they gave me new appointment letter with the same school i want but another copy of appointment letter they didn't asked me to receive it. Now i only have my appointment letter and do not know which copy of my received letter is attached in my record file. Now after 3 years in my service the babu(assitant) is threatening me that my letter is fack bcoz there is not any received copy( by me) of my changed( new) appointment letter in my record file.plz tell me who is resposible for that mistake. What should i do now.is this cause any trouble in my job. Plz help me out.