I have baseboard heaters (240) I have two hots coming in to the thermostat one black one white marked as hot I have the black wire feed and the thermostat top wire ran to the black wire of the heater I have the white wire from feed to bottom wire of thermostat and the to the white wire of the heater is this right

Rich,

Start back at the heater's breaker. What is the amperage on the breaker and is it a two pole single throw breaker? Does Black go to one side of the breaker and White to the other breaker with ground going to ground?

On the heater, Black and White should be connected to the "Hot" terminals, because bothh are supplying power to the heater. Ground should be attached to ground.

That doesn't sound right to me. If you have a double pole thermostat, 2 terminals should be marked line, and 2 load. L1 and L2 will be line. Connect the hot pair to the line terminals, and the pair to the heater to the load terminals. If the terminals aren't marked, try to see which terminals connect to which contacts. You want the 2 black wires connected to terminals that are connected when the thermostat calls for heat and the whites to the other 2. If they aren't marked, and you can't see which is which, check if there were directions for it. You can check with a meter or tester. You can post the brand and model and let somebody here identify the terminals.

Posting the name plate rating of the heater, the wire size you used, and the breaker size will allow us to verify your wiring is adequate for the heater.