Contact Customer Service toll-free at 1-800-375-5283 for:
Change of Address – If you have submitted your application and are changing your address, but have not yet received your receipt. (If you have a receipt, you can report your change of address from our website, using USCIS' Change of Address Online.)
Unusual Delay – If you have not received a receipt within the timeframe indicated below for the Service Center where you filed your application.
This info provided
here.