You should take a look at the union contract yourself, and probably also bring a copy to an employment law attorney to review with you.As a general matter, an employer is free to set wages and compensation--that is, it can pay its workers anything it wants. If there is an employment contract, including a union agreement, however, the employer must honor or obey its terms. Therefore, if the contract would require you to be paid more, your salary/wages should be increased; but if the union agreement does not require you to be paid more, then the employer would be free to not increase your pay.