How to proceed after no contact from potential employer following past felony conviction disclosure

I was sent via email a conditional offer of employment and start date along with documents to complete for authorization of a background check. I replied to the email attaching the completed forms but also preemptively included in the body of the email, without going into too much detail, a two paragraph explanation about a felony conviction that I've had in the past. The employer never responded to that email. It has been 18 days and I have not since had any contact with or recieved any mailed documents from the employer. I also have not recieved a copy of the background check results as requested. Would it be a good idea to contact them? Have they violated the law by not providing me with a letter of their decision? With the possibility that a background check was never ran after my letter of explanation of the conviction, I'm just hoping for advice on what steps I should take to move forward. Thank you.