You have run into two major problems with these group long term disability insurance policies. First, you discovered that yes, most require a repayment if you are later awarded social security disability benefits. Yes, you will likely have to repay your disability company, even though they have now terminated your benefits!
The second major discovery you made is that these companies that the disability insurance company send you to for a "free" representation in your social security disability claim are working for two "masters," you and the company that hired them. Unfortunately, we've seen a lot of dubious practices carried about by these "we'll get your social security benefits for free" companies the disability companies send people to.
So, unfortunately, you have seen the worst of these disability companies. Benefit denial followed by a request that "you pay us back out of your social security benefits."
Each contract is different, and you should consult with an experienced disability company in your area to see what you can do about your benefits.