People in the Rhode Island / South Coast MA area - Where do you get your CO2 tanks refilled? Will any Paintball supply store re-fill them for you?
If you're talking about the Cape I think there's a place near where TGI Friday's used to be off the Hyannis airport rotary, or somewhere close by there.
Sorry I can't be more help right now I'll ask someone tomorrow for the name of the place. A guy at the local brewery told me about it last week.
Here are a few I've always had good luck with:
RI Fruit & Syrup, Rte 44 between Centredale and Greenville
Corp Brothers, Niantic Ave (off Rte 10) in Cranston
ABCO Welding Supply (exchange only), Jefferson Blvd, Warwick