By purchasing something from the company, you established a business relationship with the company. As a result, even if you put your number on the National Do Not Call Registry, that company may call you for up to 36 months after your last purchase or delivery from it, or your last payment to it, unless you ask the company not to call again. In that case, the company must honor your request not to call.
An established business relationship with a company also will be created if you make an inquiry to the company, or submit an application to it. This kind of established business relationship also exists for 36 months after the inquiry or application. During this time, the company can call you.
If you give a company your written permission to call you, they may do so even if you have placed your number on the National Do Not Call Registry. However, if you ask a company with which you have an established business relationship to place your number on its own do-not-call list, it must honor your request. You should keep a record of the date you make the request.