noc for medical test

hi all.
after i finish my two years work agreement i got noc from my sponsor and i handover that noc to my new sponsor.after that i went to my country and my new sponsor email my visa to my country.then last month i came to qatar and i went to medical test at al khore medical center.when i give my passport they checked my canceled visa and they asked how u come after one month.i explained that i came with noc .but they asked so many question after said come next sunday and give small note in arabic handwriting.i can understand only that note my last exit date write there. my question is do i need noc letter for medical test?my old sponsor already went to his country.so in case i cannot contact him now..should i need any thing (like signature) from my old sponsor thanks all and pls help me