If it were me, I'd call them back to politely ask who they are and why they called, and maybe give them my bankruptcy case number. Creditors are not allowed to call again if they know you have filed.
My 10/14/05 story:
Arrived at the court clerk's office before 9AM to file my emergency petition, and there were already about 20 people in line at the door in front of me. At 9:15AM I was greeted just inside the door and my documents were scanned in (the clerk returned my documents after a few minutes.) I waited another hour to pay the $209 fee in cash, got a receipt with my case number and my 341 date. Impressive, considering the workload that day! The process was handled efficiently. I was all done by 10:30AM and on my way... the line was HUGE at that time... at least 75 people, out the door and down the hallway. === A few days later, I checked PACER, and it said my
Statement of SSN was NOT filed. (I had given it to the clerk doing the scanning, and noticed that she took it out of the pile and did not scan it... and returned it on top of the pile with a post-it with her initials on it. An hour later, the 2nd clerk who gave me my case number removed that post-it and took my docs...) === So, the next day, I brought it in and the clerk filed it,
again... seven days later, I got a note in the mail that said it must be filed within FIVE days from the date on the letter or my case would be rejected -- a few days before I had received that notice! -- SO it would have been impossible to comply if I had not happened to read about PACER, and sign up, and check in... PACER saved my butt! Filed all my remaing schedules on 10/27, one day before the due date.