Depending on my mood, I may or may not "play" with them for a little while. Calls about a credit card are always fun because I DON'T have a credit card, and I don't want one, nor do I have an Amazon account. They've been telling me for years my computer is about to crash and for a minimum fee they can make that problem they've spent the last half hour or 45 minutes "fixing" go away permanently, which is when I tell them I don't have a computer, which gets me called all kinds of nice names before they hang up on me.
Duct cleaners are always fun to play with. I always tell them I don't have ducks. Chickens, cows, pigs and fish, (the meats that are generally in my freezer) but no ducks.
It's also fun to tell "Johnny" that isn't his name, listen to him mildly protest that his name IS "Johnny" and then hang up on him. I might even mimic his accent when I do it.
If I'm in a bad mood, or they wake me up, I'm not so nice. Ask me about the Spanish lady who called privately and I'll give you the details of that call. She woke me up and I wasn't very nice.
If it's an email from someone I don't recognize, I don't bother to open it and just delete it, especially if it's a job offer for a job I never applied for. If I get a text from someone but the only thing its asking me to do is download something with no message attached, I delete it as well on the premise that if someone I know is going to send me something that I need to download via text message, they're going to start a conversation with me as well or they'll call me and let me know they're sending me something.