Not having a land line is the best and only real way of eliminating the sales/marketing calls. Use your cell phone for all calls. Being nasty to a sales rep won't discourage future calls. They'll just keep coming. Placing telemarketing calls to wireless phones is - and always has been - illegal in most cases, as stated by the FCC.
We used to get about a dozen calls after getting home from work. Many more during the day while we were at work. The do-not-call list is a freaking joke and there was no easy way to block the calls. So I terminated the land line and 99.5% of the calls are GONE. Legally telemarketers can't call cell phones. And if I get an occasional call (maybe one a month), I simply block the number on my iPhone. So simple! Evenings are no SO much more relaxing because the land line never rings. We love it!
This. I haven't had a land line in 10 years. If a telemarketer somehow manages to call me on my mobile phone, I'll wait to talk to a rep and the first thing I say is that they're calling me on my cell.
Remember that recorded line? Now it's evidence in my favor if they continue to call and I file a lawsuit.