Check en cashed by USCIS but receipt not received after 15 days

I applied for H4EAD with for I-765 on 27th October 2018, by package was received on 29th October 2018 and the check was en cashed on 2nd November 2018.

Its been 15 days since they received my documents and 7 days since they en cashed my check, but I still havent received the receipt number. I’m getting worried now. Please advice as to what should be my next step. When should I contact them?

Would really appreciate your advice.

Don’t worry. Notice of Receipt will come by USPS mail and it can take upto 3 weeks.