First of all, sales calls to cellular phones in the United States are illegal. make the callers aware of that and the calls should stop.
You can also install google voice and have similar abilities to what you described, but that requires that the number be added to your contacts, IIRC.
I use this app:
It works wonderfully at blocking unwanted calls and you can add numbers t it not found in your contact list. The number essentially rings once and the person calling gets hung up on. Th elite version is the same as the paid version, but with a limit on the number of numbers you can block. the paid version has no limit.