The commissioner and State Chemist are authorized and empowered to refuse registration of a soil or plant amendment if they find the brand of soil or plant amendment violates any section of this chapter or the rules and regulations promulgated under this chapter. The commissioner and State Chemist are authorized and empowered to cancel the registration of any brand of soil or plant amendments upon satisfactory evidence that the registrant has used fraudulent or deceptive practices in the evasions or attempted evasions of the provisions of this chapter, or any rules or regulations promulgated thereunder; provided, that no registration shall be revoked until the registrant shall have been given the opportunity to appear for a hearing by the commissioner and State Chemist.