WHERE is our I171H???

We sent our I600A in on Febuary 14, (Valentine's Day). We were given the filing date of March 3rd, and given the notice to be fingerprinted a month later. Unfortunately, my mom's prints were rejectected so she got a date to be re-fingerprinted, she went in and did the refingerprinting about two weeks ago. The people who took her prints seemed very unhopeful that her prints even took this time, but said we would find out in about a week or two, well its been two weeks, so hopefully it was all good. Our social worker said she had never heard of people's prints not taking the second time, so we are probably ok and shouldn't worry about it. If the prints did take that means our I171H should be in the mail and we should be getting it, but its not here!!! So, Where is our I171H???