That voltage is unusually high. I would normally expect no more than 264 if you have normal 120/240 single phase service. You might check your meter, and then if the meter is good, ask your power company what is going on. If you have 3 phase power, then some more study is needed.
So the pump is not running, and you have zero current. Terminals R, Y, and B are wired to the pump. Either you have a broken wire/connection, or your pump is bad.