HCL Technologies — Pending Work experience letter for Visa Application

Address:

HCL Technologies Ltd. | Technology Hub, SEZ Plot No. 3A, Sector 126 | Noida – 201304, India.

I am trying to reach HCL Technologies Team over phone and email to get Work experience letter in certain format for my VISA application.
They are not just responding to calls or emails.
It is urgent for me but really cant reach anyone.
I have tried raising support request as well. No response from there as well.

I have received letters from all previous company. My visa application is pending just because of this document.