Any sales calls that are made without your express permission are unwanted and a violation of your phone privacy.
The best thing you can do when you receive calls you don't want, regardless if they are unsolicited or not, is to stop telemarketers and annoying calls by requesting to be placed on the internal do-not-call-list of the company. You should also sign up your phone numbers with the National Do Not Call Registry. This will help reduce the amount of unsolicited calls you receive and enable you to file complaints against those callers who believe they are above the law.