Answer
(Fatwa: 291=284/D)
Azan is an emblem of Islam. It is imperative to pronounce the words of Azan correctly. You should convince the Muezzin politely to learn the correct pronunciation of Azan; otherwise all the people of the locality will be sinful.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband