H1B extension notice receipt showing document received date two days after 1-94 expiration:

I came to US in March 2014 and my H1B was expiring on June 30 2014, I got 1-94 of same date i.e. valid till June 30 2014, My employer sent my extension file (Under Premium) to USCIS on 24 June 2014 for extension and got UPS confirmation that documents are delivered on 24 June 2014.we waited for receipt but finally we got receipt notice on July 4 and document received date in notice is 3 July 2014.

Now my concern is I am still in US and working with my employer, so want to know if there is something illegal in my case or is there any way we can update USCIS that we have applied in time and delay is from there end.

Any suggestion or feedback is highly appreciated.