The phrase "was contingent on" means that something is dependent on another thing happening or being in place for it to occur. If you're looking for synonyms, you could use phrases such as "relied on," "hinged upon," or "was conditional on." Other options include "depended on," "was subject to," or "hung in the balance of." If you're more interested in using single words, you could consider substitutes like "rested on," "was based on," "was determined by," or "was influenced by." Choosing the right synonym can help you express yourself more clearly and effectively in your writing.