The tax form that the Canada Revenue Agency requires you to fill out in order to close your Business Number account (BN) is located at the following CRA web page: http://www.cra-arc.gc.ca/E/pbg/gf/rc145/rc145-10e.pdf . Once you fill out the tax form, then you must send it to your local tax services office. If you wish to speak with someone at the Canada Revenue Agency regarding this tax form or any other issue relating to the closing of your Business Number account (BN), then you may reach a CRA representative at the following toll-free telephone number: 1-800-959-5525.