Yes, there are cases where an attorney cannot work on a contingency fee basis. Since the American Bar Association reserves this fee structure for civil cases, no criminal cases can work on a contingency fee basis. Family law cases are the other exception to this pay structure. Another instance where an attorney cannot collect a percentage of your settlement is when it goes against statutory laws or is unreasonable to collect. When you have a case that does not qualify for a contingency fee, your lawyer may use other payment options.