Voltas — Bad smell from AC

Address: Mathrusree nagar, Miyapur, Hyderabad, Telangana

I have four 1.5ton ACs. Bought them on May 2019. Barely used ACs in 2019 as I am out of country. For all of them Bad smell comes when I start an AC and after cooling whenever compressor restarts bad smell will come.. I am having this issue from 2020 onwards. I gave around 30 complaints. Dozens of technicians visited my home and did normal wash, chemical wash even fire treatment. With in one week the problem occurs. I am frustrated with Voltas service. Attaching my last Chemical was receipt. Bad smell started after 2 days only. I purchased these Voltas ACs because it is TATA product. But, I lost trust on them.