Stating the hopefully obvious. Don't talk to an outbound caller claiming to be Dish. Tell them you will call Dish back. If they are legit (and this one is not), they will leave notes on the account for the next agent. The only legit calls I can think of from Dish would be our Outbound STB Health folks, when you are internet connected, and they notice your receiver is having signal strength issues. They will leave notes on the account. Also, the audit folks that have been mentioned here. And yes, they will leave notes on the account too, and if you call back, the agent can give you the toll free number for that group.
So, if you get a call from Dish, tell them you will call Dish yourself. If legit, they will leave notes.