worried about my case , has this happen to anyone?

I was wondering if any you guys received a request for evidence 2x?
Well I my lawyer filed in December 2012 and on January 28 I with for my biometric finger prints and then in March I received request for evidence. But neither I or nor my lawyer ever receive the letter on the mail so after waiting a month I decide to call the USCI the the person over there told me that it was error in the system and there was no request ever sent. I was so happy to hear that , and it was simply work load(a lot of app were slowing the process). On May 5 ,I got another request for evidence,has this happen to any of you folks? not sure what to think and how long does anyone know how long the request of evidence take once its is send?
thanks you all for any information

Call again and explain what happened before.

have you recalled to see if they made a mistake again ?

it happen to my I got a status update on 2/27/13 and it was RFE so after wating two weeks for the RFE letter my case was update again on 3/13/13 saying that I got a RFE so it took 5 days from.the second update to my actual letter

Probably a glitch but call again and ask or wait 5 days to see if your case gets updated

Yea this doesnt sound like a real problem to me. Sorry its taking you extra time though. Things like this can be resolved via phone calls so dont worry.