The phrase "were subjected to" basically means being exposed to or undergoing something. There are several synonyms that can be used to convey a similar message. Some of the best options are "endured," "experienced," "underwent," "suffered," "faced," "encountered," "confronted," "endured," and "survived." Depending on the context, some other synonyms like "went through," "passed through," "weathered," and "withstood" can also be utilized. It is always good to have a vast range of synonyms at your disposal as it helps in avoiding repetitions and keeping your writing exciting and fresh.