HDFC Fastag — Fastag not working

I have purchased a fastag from hdfc (Online) in december 2019
It was not working from beginning (Not reading in toll plaza)
I had raised complaint in their customer care over phone many times, each time they asked me to try again in toll plaza and let them know
At last on may 20, 2020 they asked me to send email to fastag. [protected]@insolutionsglobal.com, i sent email (Attached the photo of fastag sticker). But i didn't get any reply from their side,
Again i called them many times to know status of my complaint, most of times they are saying their site is down so could not check, at last on june 1st they told me it will be solved in 24 hrs and i will get a call back from their side. Till now no reply.