I got an RFE on my petition for H1B

[bidge]

Hi guys, my employers recently filed my petition for an H1B, my employer is a Non-Profit employer so the H1B is directly granted without the need of going through the lottery. I received an RFE to prove that I was previously employed on my OPT, where I was employed as an unpaid intern and they are asking for the pay stubs

I was wondering if anyone from here has been through the similar situation and if yes how did you prove that you were employed and how much time it took to review your petition?

Thank you would really appreciate your response!