Did you see any kind of company logo on his car? If he's advertising on CL, that immediately raises a red flag in my mind. Search for his number online, check the local BBB. No record? You got bilked.

It's remotely possible that he was legit, but to be absolutely certain, you should contact DTV and talk to them about it.

Do a search for DTV International and look at their page, see if it makes sense to you, see if you can relate any of their packages to what he was offering.