You are in no way obligated to speak to them. Politely decline to speak with the other driver's insurance company, give them your lawyer's name and contact information, and advise them to speak directly to your attorney from now on. It's important not to provide any information whatsoever to the at fault driver's insurance company, as they may try to lead you into saying something makes liability unclear or otherwise makes your case difficult to pursue.
Then call us. We are Maryland accident lawyers who can help steer you in the right direction immediately. During work hours, call the office at (410) 766-4044, and after hours or weekends, call my cell at (443) 253-7713.