Previous employment letter required for stamping?


Can someone help me with right answers,

I came to us on h1B thru company A and switched my job after 2 years to company B and spent 3 months with company B and need visa stamping now.

Company A is refused to provide experience letter and they ask for 12,000 $ for it and behaving very rude.
I have no money dues with Company A.

Please guide me is that experience letter is mandatory for Visa stamping

Some of my friends suggesting to get affidavits form my supervisors and previous colleagues.

Does this affidavit is equal to an experience letter?

Please guide,

It is not required to have A’s experience letter for visa stamping. Just carry some recent payslips to show that you indeed worked for them and were paid.

Experience letters may be required when green card is filed.