In D.C. workers compensation, insurance companies can stop your benefits for any reason - or no reason at all. All they have to do is file a notice of controversion, a simple forming stating a reason.
What are some of the reasons for an insurance company to stop your benefits?
They can have you examined by one of their doctors (an IME - insurance medical exam), say they are still investigating the claim, or that they don't have evidence of any current disability, or you didn't "cooperate" with a vocational counselor. They can basically make up a reason.
Then its up to you to win your case and get the benefits reinstated - but that could take many, many months by the time you go to a hearing and an Administrative Law Judge issues a decision.
That's why we take steps so our clients don't benefits cut off in the first place and act immediately when they do. We cover a lot of this in the book Protect Your Rights: The Ultimate Guide to D.C. Workers Compensation or you can call us at (202) 393 - 3320 and speak to a live person who will help you and can tell you what we do in this situation.