Has anybody experienced this ?

I'm getting a bit worried. I had my green card interview on August 1st with my wife, but they couldn't approve me because of a speeding ticket I got. The officer said they'd send a letter telling me to sort it out and mail proof, but I shouldn't do act on the letter until I sort out the outstanding speeding ticket. He said it would take 7-10 working days before I receive the letter but it's been 1 month and I still haven't heard from USCIS. Is this normal? Should I be worried? What should I do next?