You want to store a reference to an object in AccountService.provider, but the trait has only a "static" getAccount() without &self, so there's no object involved there. Your trait is not for provider.getAccount(), but only for <SomeType as AccountProvider>::getAccount().
Changing fn getAccount() to fn getAccount(&self) solves the problem.
BTW, a temporary, scope-limited AccountService<'a> might be pain to use and spread lifetime annotations throughout entire codebase. Usually things are stored in structs via Box<dyn AccountProvider> that makes structs self-contained and possible to store permanently.