From the description, it's not an honest mistake. That it's a small amount doesn't matter - some people are just made that way, they like to screw over others and there's nothing too petty. I also push domains to established companies when the figure is under $1000, and never had any problems. It makes the sales process easier, and there's relatively little risk in my experience. Nothing to be ashamed of, professionals in all fields have to deal with clients who can't/won't pay.
This is a good reminder to always follow up telephone conversations with emails repeating what was agreed to. This also helps to prevent misunderstandings.
If I could take them to small claims court, maybe I would. Not so much for the money, but because I'd hate being treated that way. Drum up as much publicity as you can, and do your best to see that you cost them much more than they saved by screwing you over.<style>.adslot-overlay {position: absolute; font-family: arial, sans-serif; background-color: rgba(0,0,0,0.65); border: 2px solid rgba(0,0,0,0.65); color: white !important; margin: 0; z-index: 2147483647; text-decoration: none; box-sizing: border-box; text-align: left;}.adslot-overlay-iframed {top: 0; left: 0; right: 0; bottom: 0;}.slotname {position: absolute; top: 0; left: 0; right: 0; font-size: 13px; font-weight: bold; padding: 3px 0 3px 6px; vertical-align: middle; background-color: rgba(0,0,0,0.45); text-overflow: ellipsis; white-space: nowrap; overflow: hidden;}.slotname span {text-align: left; text-decoration: none; text-transform: capitalize;}.revenue {position: absolute; bottom: 0; left: 0; right: 0; font-size: 11px; padding: 3px 0 3px 6px; vertial-align: middle; text-align: left; background-color: rgba(0,0,0,0.45); font-weight: bold; text-overflow: ellipsis; overflow: hidden; white-space: nowrap;}.revenue .name {color:
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